Rare earth hard alloy and preparation method and application thereof
11788174 · 2023-10-17
Assignee
Inventors
- Yong Du (Jiangxi, CN)
- Jian Lv (Jiangxi, CN)
- Keke Chang (Jiangxi, CN)
- Weibin Zhang (Jiangxi, CN)
- Ming Lou (Jiangxi, CN)
- Zepeng Li (Jiangxi, CN)
- Yangqing Lv (Jiangxi, CN)
Cpc classification
International classification
C22C1/051
CHEMISTRY; METALLURGY
Abstract
The present invention provides a rare earth hard alloy and a preparation method and application thereof. The rare earth hard alloy includes 6 to 15 wt % of a binding phase and the balance of a hard phase, wherein the binding phase includes 30 to 50 wt % of Ni.sub.3Al, 0.1 to 0.5 wt % of a rare earth element and the balance of Ni. According to the rare earth hard alloy provided by the invention, the Ni—Ni.sub.3Al-rare earth element (e.g., Ni—Ni.sub.3Al—Y)-based binding phase is strengthened by Ni.sub.3Al, and an ordered strengthening phase is formed and is diffused and distributed in the binding phase, such that the rare earth hard alloy has a better high-temperature oxidation resistance, a better room-temperature fracture toughness and a better high-temperature bending strength than a conventional hard alloy.
Claims
1. A rare earth hard alloy, comprising, based on a weight of the hard alloy, 6 to 15 wt % of a binding phase and balance of a hard phase, wherein based on a weight of the binding phase, the binding phase comprises 30 to 50 wt % of Ni.sub.3Al, 0.1 to 0.5 wt % of a rare earth element and balance of Ni, the rare earth element being Y; based on the weight of the hard phase, the hard phase includes 30 to 50 wt % of NbC and balance of WC; and a preparation method of the rare earth hard alloy comprises steps of: S1. mixing Ni.sub.3Al powders and a rare earth element source solution, and performing a first wet-milling treatment to obtain a first material; S2. performing a high-temperature treatment on the first material to obtain a second material; S3. mixing the second material, NbC powders, WC powders and Ni powders and performing a second wet-milling treatment to obtain a mixture; and S4. drying, pressing and sintering the mixture to obtain the rare earth hard alloy.
2. The rare earth hard alloy according to claim 1, characterized in that, the WC powder has a particle size of from 0.6 to 3.0 μm.
3. The rare earth hard alloy according to claim 1, characterized in that, in the rare earth element source solution, a rare earth element is Y; and the rare earth element source solution is a salt solution of the rare earth element.
4. The rare earth hard alloy according to claim 3, characterized in that, the rare earth element source solution is an anhydrous nitrate solution of the rare earth element.
5. The rare earth hard alloy according to claim 4, characterized in that, the rare earth element source solution is an anhydrous yttrium nitrate alcoholic solution.
6. The rare earth hard alloy according to claim 1, characterized in that, by a total weight of 100% of the Ni.sub.3Al powders, the rare earth element in the rare earth element source solution and the Ni powders, the Ni.sub.3Al powders are present in an amount of from 30 to 50%, and the rare earth element in the rare earth element source solution is present in an amount of from 0.1 to 0.5%.
7. The rare earth hard alloy according to claim 1, characterized in that, by a total weight of 100% of the NbC powders and the WC powders, the NbC powders are present in an amount of from 30 to 50 wt %.
8. The rare earth hard alloy according to claim 1, characterized in that, in the step S1, the first wet-milling treatment is performed for 6 to 12 h; and/or in the step S2, the high-temperature treatment is performed at a temperature of from 900 to 1000° C.; in the step S3, the second wet-milling treatment is performed for 18 to 36 h; and/or in the step S4, the sintering treatment is performed at a temperature of from 1410° C. to 1500° C.
9. The rare earth hard alloy according to claim 8, characterized in that, in the step S2, the high-temperature treatment is performed under a vacuum condition.
10. The rare earth hard alloy according to claim 9, characterized in that, the high-temperature treatment is performed under a vacuum condition of from 0.01 to 0.1 Pa.
Description
BRIEF DESCRIPTION OF DRAWINGS
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DETAILED DESCRIPTION
(8) The present invention is described in detail by means of examples below, but the scope of protection of the present invention is not limited to the following description.
(9) Where specific conditions are not specified in the examples, conventional conditions or those recommended by the manufacturer are followed. The reagents or instruments used without specifying the manufacturer are all conventional products that can be obtained by means of market purchase. NbC powder, Ni powder and NbC powder used in the following examples are all conventional commercially-available products.
Example 1
(10) In the example, the contents of Ni.sub.3Al, Y and Ni as a binding phase account for 6% of the total content of a hard phase and the binding phase, and WC powder has a particle size of 0.6 μm.
(11) Example 1 provides a rare earth hard alloy, a preparation method of which is as follows:
(12) (1) Ni.sub.3Al powder and an anhydrous yttrium nitrate alcoholic solution were mixed and subjected to a first wet-milling treatment for 6 h to obtain a first material; wherein the amount of the added Ni.sub.3Al powder accounted for 30 wt % of that of the binding phase, and the amount of yttrium in the anhydrous yttrium nitrate alcoholic solution added accounted for 0.1 wt % of that of the binding phase;
(13) (2) the first material was subjected to a high-temperature treatment at 900° C. under a vacuum condition of 0.01 Pa to obtain a second material;
(14) (3) NbC powder, WC powder and Ni powder were added into the second material and wet milled again for 18 h to obtain a mixture; wherein the total amount of the WC powder accounted for 70 wt % of that of the hard phase, the amount of the added NbC powder accounted for 30 wt % of that of the hard phase, and the amount of the added Ni powder accounted for 69.9 wt % of that of the binding phase; and
(15) (4) the mixture was spray dried and compacted, and the green compact was subjected to a low-pressure liquid phase sintering at 1500° C. to obtain a WC—NbC—(Ni—Ni.sub.3Al—Y) rare earth hard alloy.
Example 2
(16) In the example, the contents of Ni.sub.3Al, Y and Ni as a binding phase account for 6% of the total content of a hard phase and the binding phase, and WC powder has a particle size of 1.5 μm.
(17) Example 2 provides a rare earth hard alloy, a preparation method of which is as follows:
(18) (1) Ni.sub.3Al powder and an anhydrous yttrium nitrate alcoholic solution were mixed and subjected to a first wet-milling treatment for 9 h to obtain a first material; wherein the amount of the added Ni.sub.3Al powder accounted for 40 wt % of that of the binding phase, and the amount of yttrium in the anhydrous yttrium nitrate alcoholic solution added accounted for 0.3 wt % of that of the binding phase;
(19) (2) the first material was subjected to a high-temperature treatment at 950° C. under a vacuum condition of 0.05 Pa to obtain a second material;
(20) (3) NbC powder, WC powder and Ni powder were added into the second material and wet milled again for 27 h to obtain a mixture; wherein the total amount of the WC powder accounted for 60 wt % of that of the hard phase, the amount of the added NbC powder accounted for 40 wt % of that of the hard phase, and the amount of the added Ni powder accounted for 59.7 wt % of that of the binding phase; and
(21) (4) the mixture was spray dried and compacted, and the green compact was subjected to a low-pressure liquid phase sintering at 1500° C. to obtain a WC—NbC—(Ni—Ni.sub.3Al—Y) rare earth hard alloy, i.e., WC-37.6% NbC-6% (Ni—Ni.sub.3Al—Y).
Example 3
(22) In the example, the contents of Ni.sub.3Al, Y and Ni as a binding phase account for 6% of the total content of a hard phase and the binding phase, and WC powder has a particle size of 3.0 μm.
(23) Example 3 provides a rare earth hard alloy, a preparation method of which is as follows:
(24) (1) Ni.sub.3Al powder and an anhydrous yttrium nitrate alcoholic solution were mixed and subjected to a first wet-milling treatment for 12 h to obtain a first material; wherein the amount of the added Ni.sub.3Al powder accounted for 50 wt % of that of the binding phase, and the amount of yttrium in the anhydrous yttrium nitrate alcoholic solution added accounted for 0.5 wt % of that of the binding phase;
(25) (2) the first material was subjected to a high-temperature treatment at 1000° C. under a vacuum condition of 0.1 Pa to obtain a second material;
(26) (3) NbC powder, WC powder and Ni powder were added into the second material and wet milled again for 36 h to obtain a mixture; wherein the total amount of the WC powder accounted for 50 wt % of that of the hard phase, the amount of the added NbC powder accounted for 50 wt % of that of the hard phase, and the amount of the added Ni powder accounted for 49.5 wt % of that of the binding phase; and
(27) (4) the mixture was spray dried and compacted, and the green compact was subjected to a low-pressure liquid phase sintering at 1500° C. to obtain a WC—NbC—(Ni—Ni.sub.3Al—Y) rare earth hard alloy, i.e., WC-37.6% NbC-6% (Ni—Ni.sub.3Al—Y).
Example 4
(28) In the example, the contents of Ni.sub.3Al, Y and Ni as a binding phase account for 10% of the total content of a hard phase and the binding phase, and WC powder has a particle size of 0.6 μm.
(29) Example 4 provides a rare earth hard alloy, a preparation method of which is as follows:
(30) (1) Ni.sub.3Al powder and an anhydrous yttrium nitrate alcoholic solution were mixed and subjected to a first wet-milling treatment for 6 h to obtain a first material; wherein the amount of the added Ni.sub.3Al powder accounted for 30 wt % of that of the binding phase, and the amount of yttrium in the anhydrous yttrium nitrate alcoholic solution added accounted for 0.1 wt % of that of the binding phase;
(31) (2) the first material was subjected to a high-temperature treatment at 950° C. under a vacuum condition of 0.05 Pa to obtain a second material;
(32) (3) NbC powder, WC powder and Ni powder were added into the second material and wet milled again for 18 h to obtain a mixture; wherein the total amount of the WC powder accounted for 70 wt % of that of the hard phase, the amount of the added NbC powder accounted for 30 wt % of that of the hard phase, and the amount of the added Ni powder accounted for 69.9 wt % of that of the binding phase; and
(33) (4) the mixture was spray dried and compacted, and the green compact was subjected to a low-pressure liquid phase sintering at 1450° C. to obtain a WC—NbC—(Ni—Ni.sub.3Al—Y) rare earth hard alloy.
Example 5
(34) In the example, the contents of Ni.sub.3Al, Y and Ni as a binding phase account for 10% of the total content of a hard phase and the binding phase, and WC powder has a particle size of 1.5 μm.
(35) Example 5 provides a rare earth hard alloy, a preparation method of which is as follows:
(36) (1) Ni.sub.3Al powder and an anhydrous yttrium nitrate alcoholic solution were mixed and subjected to a first wet-milling treatment for 9 h to obtain a first material; wherein the amount of the added Ni.sub.3Al powder accounted for 40 wt % of that of the binding phase, and the amount of yttrium in the anhydrous yttrium nitrate alcoholic solution added accounted for 0.3 wt % of that of the binding phase;
(37) (2) the first material was subjected to a high-temperature treatment at 1000° C. under a vacuum condition of 0.1 Pa to obtain a second material;
(38) (3) NbC powder, WC powder and Ni powder were added into the second material and wet milled again for 27 h to obtain a mixture; wherein the total amount of the WC powder accounted for 60 wt % of that of the hard phase, the amount of the added NbC powder accounted for 40 wt % of that of the hard phase, and the amount of the added Ni powder accounted for 59.7 wt % of that of the binding phase; and
(39) (4) the mixture was spray dried and compacted, and the green compact was subjected to a low-pressure liquid phase sintering at 1450° C. to obtain a WC—NbC—(Ni—Ni.sub.3Al—Y) rare earth hard alloy of the invention, i.e., WC-36% NbC-10% (Ni—Ni.sub.3Al—Y).
Example 6
(40) In the example, the contents of Ni.sub.3Al, Y and Ni as a binding phase account for 10% of the total content of a hard phase and the binding phase, and WC powder has a particle size of 3.0 μm.
(41) Example 6 provides a rare earth hard alloy, a preparation method of which is as follows:
(42) (1) Ni.sub.3Al powder and an anhydrous yttrium nitrate alcoholic solution were mixed and subjected to a first wet-milling treatment for 12 h to obtain a first material; wherein the amount of the added Ni.sub.3Al powder accounted for 50 wt % of that of the binding phase, and the amount of yttrium in the anhydrous yttrium nitrate alcoholic solution added accounted for 0.5 wt % of that of the binding phase;
(43) (2) the first material was subjected to a high-temperature treatment at 900° C. under a vacuum condition of 0.01 Pa to obtain a second material;
(44) (3) NbC powder, WC powder and Ni powder were added into the second material and wet milled again for 36 h to obtain a mixture; wherein the total amount of the WC powder accounted for 50 wt % of that of the hard phase, the amount of the added NbC powder accounted for 50 wt % of that of the hard phase, and the amount of the added Ni powder accounted for 49.5 wt % of that of the binding phase; and
(45) (4) the mixture was spray dried and compacted, and the green compact was subjected to a low-pressure liquid phase sintering at 1450° C. to obtain a WC—NbC—(Ni—Ni.sub.3Al—Y) rare earth hard alloy.
Example 7
(46) In the example, the contents of Ni.sub.3Al, Y and Ni as a binding phase account for 15% of the total content of a hard phase and the binding phase, and WC powder has a particle size of 0.6 μm.
(47) Example 7 provides a rare earth hard alloy, a preparation method of which is as follows:
(48) (1) Ni.sub.3Al powder and an anhydrous yttrium nitrate alcoholic solution were mixed and subjected to a first wet-milling treatment for 6 h to obtain a first material; wherein the amount of the added Ni.sub.3Al powder accounted for 30 wt % of that of the binding phase, and the amount of yttrium in the anhydrous yttrium nitrate alcoholic solution added accounted for 0.1 wt % of that of the binding phase;
(49) (2) the first material was subjected to a high-temperature treatment at 1000° C. under a vacuum condition of 0.1 Pa to obtain a second material;
(50) (3) NbC powder, WC powder and Ni powder were added into the second material and wet milled again for 18 h to obtain a mixture; wherein the total amount of the WC powder accounted for 70 wt % of that of the hard phase, the amount of the added NbC powder accounted for 30 wt % of that of the hard phase, and the amount of the added Ni powder accounted for 69.9 wt % of that of the binding phase; and
(51) (4) the mixture was spray dried and compacted, and the green compact was subjected to a low-pressure liquid phase sintering at 1410° C. to obtain a WC—NbC—(Ni—Ni.sub.3Al—Y) rare earth hard alloy.
Example 8
(52) In the example, the contents of Ni.sub.3Al, Y and Ni as a binding phase account for 15% of the total content of a hard phase and the binding phase, and WC powder has a particle size of 1.5 μm.
(53) Example 8 provides a rare earth hard alloy, a preparation method of which is as follows:
(54) (1) Ni.sub.3Al powder and an anhydrous yttrium nitrate alcoholic solution were mixed and subjected to a first wet-milling treatment for 9 h to obtain a first material; wherein the amount of the added Ni.sub.3Al powder accounted for 40 wt % of that of the binding phase, and the amount of yttrium in the anhydrous yttrium nitrate alcoholic solution added accounted for 0.3 wt % of that of the binding phase;
(55) (2) the first material was subjected to a high-temperature treatment at 900° C. under a vacuum condition of 0.01 Pa to obtain a second material;
(56) (3) NbC powder, WC powder and Ni powder were added into the second material and wet milled again for 27 h to obtain a mixture; wherein the total amount of the WC powder accounted for 60 wt % of that of the hard phase, the amount of the added NbC powder accounted for 40 wt % of that of the hard phase, and the amount of the added Ni powder accounted for 59.7 wt % of that of the binding phase; and
(57) (4) the mixture was spray dried and compacted, and the green compact was subjected to a low-pressure liquid phase sintering at 1410° C. to obtain a WC—NbC—(Ni—Ni.sub.3Al—Y) rare earth hard alloy, i.e., WC-34% NbC-15% (Ni—Ni.sub.3Al—Y).
Example 9
(58) In the example, the contents of Ni.sub.3Al, Y and Ni as a binding phase account for 15% of the total content of a hard phase and the binding phase, and WC powder has a particle size of 3.0 μm.
(59) Example 9 provides a rare earth hard alloy, a preparation method of which is as follows:
(60) (1) Ni.sub.3Al powder and an anhydrous yttrium nitrate alcoholic solution were mixed and subjected to a first wet-milling treatment for 12 h to obtain a first material; wherein the amount of the added Ni.sub.3Al powder accounted for 50 wt % of that of the binding phase, and the amount of yttrium in the anhydrous yttrium nitrate alcoholic solution added accounted for 0.5 wt % of that of the binding phase;
(61) (2) the first material was subjected to a high-temperature treatment at 950° C. under a vacuum condition of 0.05 Pa to obtain a second material;
(62) (3) NbC powder, WC powder and Ni powder were added into the second material and wet milled again for 36 h to obtain a mixture; wherein the total amount of the WC powder accounted for 50 wt % of that of the hard phase, the amount of the added NbC powder accounted for 50 wt % of that of the hard phase, and the amount of the added Ni powder accounted for 49.5 wt % of that of the binding phase; and
(63) (4) the mixture was spray dried and compacted, and the green compact was subjected to a low-pressure liquid phase sintering at 1410° C. to obtain a WC—NbC—(Ni—Ni.sub.3Al—Y) rare earth hard alloy.
(64) The proportions of the raw materials and preparation parameters of Examples 1 to 9 are listed in
(65) Table 1 below, and each of the percentages (%) in the table indicates the mass percentage of the corresponding substance in the total of the hard phase and the binding phase.
(66) TABLE-US-00001 TABLE 1 Addition Addition First Addition Second Content WC amount amount wet- Treatment Vacuum amount Addition Addition wet- Sintering of particle of of milling temperature/ condition/ of amount of amount milling temperature/ binding size/μm Ni.sub.3Al/% yttrium/% time/h ° C. Pa NbC/% WC/% of Ni/% time/h ° C. phase/% Example 1 0.6 1.8 0.006 6 900 1.01 28.2 65.8 4.194 18 1,500 6 Example 2 1.5 2.4 0.018 9 950 0.05 37.6 56.4 3.582 27 1,500 6 Example 3 3.0 3.0 0.030 12 1,000 0.1 47.0 47.0 2.970 36 1,500 6 Example 4 0.6 3.0 0.010 6 900 0.05 27.0 63.0 6.990 18 1,450 10 Example 5 1.5 4.0 0.030 9 950 0.1 36.0 54.0 5.970 27 1,450 10 Example 6 3.0 5.0 0.050 12 1,000 0.01 45.0 45.0 4.950 36 1,450 10 Example 7 0.6 4.5 0.015 6 900 0.1 25.5 59.5 10.485 18 1,410 15 Example 8 1.5 6.0 0.045 9 950 0.01 34.0 51.0 8.955 27 1,410 15 Example 9 3.0 7.5 0.075 12 1,000 0.05 42.5 42.5 7.425 36 1,410 15
Comparative Example 1
(67) In Comparative Example 1, the contents of Ni.sub.3Al and Y as a binding phase account for 6% of the total content of a hard phase and the binding phase, and WC powder serves as the hard phase and has a particle size of 1.5 μm.
(68) Comparative Example 1 provides a hard alloy, a preparation method of which is as follows:
(69) (1) Ni.sub.3Al powder and an anhydrous yttrium nitrate alcoholic solution were mixed and subjected to a first wet-milling treatment for 9 h to obtain a first material; wherein the amount of the added Ni.sub.3Al powder accounted for 40 wt % of that of the binding phase, and the amount of yttrium in the anhydrous yttrium nitrate alcoholic solution added accounted for 0.3 wt % of that of the binding phase;
(70) (2) the first material was subjected to a high-temperature treatment at 950° C. under a vacuum condition of 0.05 Pa to obtain a second material;
(71) (3) WC powder was added into the second material and wet milled again for 27 h to obtain a mixture; wherein the total amount of the WC powder accounted for 94 wt % of the total content of the hard phase and the binding phase; and
(72) (4) the mixture was spray dried and compacted, and the green compact was subjected to a low-pressure liquid phase sintering at 1500° C. to obtain a WC-6% (Ni.sub.3Al—Y) hard alloy, i.e., WC-6% (Ni.sub.3Al—Y).
Comparative Example 2
(73) In Comparative Example 2, the contents of Ni.sub.3Al and Y as a binding phase account for 10% of the total content of a hard phase and the binding phase, and WC powder serves as the hard phase and has a particle size of 1.5 μm.
(74) Comparative Example 2 provides a hard alloy, a preparation method of which is as follows:
(75) (1) Ni.sub.3Al powder and an anhydrous yttrium nitrate alcoholic solution were mixed and subjected to a first wet-milling treatment for 9 h to obtain a first material; wherein the amount of the added Ni.sub.3Al powder accounted for 40 wt % of that of the binding phase, and the amount of yttrium in the anhydrous yttrium nitrate alcoholic solution added accounted for 0.3 wt % of that of the binding phase;
(76) (2) the first material was subjected to a high-temperature treatment at 1000° C. under a vacuum condition of 0.1 Pa to obtain a second material;
(77) (3) WC powder was added into the second material and wet milled again for 27 h to obtain a mixture; wherein the total amount of the WC powder accounted for 90 wt % of the total content of the hard phase and the binding phase; and
(78) (4) the mixture was spray dried and compacted, and the green compact was subjected to a low-pressure liquid phase sintering at 1450° C. to obtain a WC-10% (Ni.sub.3Al—Y) hard alloy, i.e., WC-10% (Ni.sub.3Al—Y).
Comparative Example 3
(79) In Comparative Example 3, the contents of Ni.sub.3Al and Y as a binding phase account for 15% of the total content of a hard phase and the binding phase, and WC powder serves as the hard phase and has a particle size of 1.5 μm.
(80) Comparative Example 3 provides a hard alloy, a preparation method of which is as follows:
(81) (1) Ni.sub.3Al powder and an anhydrous yttrium nitrate alcoholic solution were mixed and subjected to a first wet-milling treatment for 9 h to obtain a first material; wherein the amount of the added Ni.sub.3Al powder accounted for 40 wt % of that of the binding phase, and the amount of yttrium in the anhydrous yttrium nitrate alcoholic solution added accounted for 0.3 wt % of that of the binding phase;
(82) (2) the first material was subjected to a high-temperature treatment at 900° C. under a vacuum condition of 0.01 Pa to obtain a second material;
(83) (3) WC powder was added into the second material and wet milled again for 27 h to obtain a mixture; wherein the total amount of the WC powder accounted for 85 wt % of the total content of the hard phase and the binding phase; and
(84) (4) the mixture was spray dried and compacted, and the green compact was subjected to a low-pressure liquid phase sintering at 1450° C. to obtain a WC-15% (Ni.sub.3Al—Y) hard alloy, i.e., WC-15% (Ni.sub.3Al—Y).
Comparative Example 4
(85) In Comparative Example 4, the content of Ni powder as a binding phase accounts for 10% of the total content of a hard phase and the binding phase, and WC powder has a particle size of 1.5 μm.
(86) Comparative Example 4 provides a hard alloy, a preparation method of which is as follows:
(87) (1) WC powder, NbC powder and Ni powder were wet milled for 27 h to obtain a mixture; wherein the total amount of the WC powder accounted for 54 wt %, the amount of the added NbC powder accounted for 36 wt %, and the amount of the added Ni powder accounted for 10 wt %; and
(88) (2) the mixture was spray dried and compacted, and the green compact was subjected to a low-pressure liquid phase sintering at 1450° C. to obtain a WC-36% NbC-10% Ni hard alloy, i.e., (WC-36% NbC-10% Ni).
Comparative Example 5
(89) In Comparative Example 5, the contents of Ni.sub.3Al, Y and Ni as a binding phase account for 10% of the total content of a hard phase and the binding phase, and WC powder has a particle size of 1.5 μm.
(90) Comparative Example 5 provides a hard alloy, a preparation method of which is as follows:
(91) (1) the first portion of WC powder and Ni.sub.3Al powder were mixed with an anhydrous yttrium nitrate alcoholic solution and subjected to a first wet-milling treatment for 9 h to obtain a first material; wherein the amount of the added Ni.sub.3Al powder accounted for 40 wt % of that of the binding phase, and the amount of yttrium in the anhydrous yttrium nitrate alcoholic solution added accounted for 0.3 wt % of that of the binding phase;
(92) (2) the first material was subjected to a high-temperature treatment at 1000° C. under a vacuum condition of 0.1 Pa to obtain a second material;
(93) (3) WC powder and Ni powder were added into the second material and wet milled again for 27 h to obtain a mixture; wherein the total amount of the WC powder accounted for 90 wt % of the total content of the hard phase and the binding phase, and the amount of the added Ni powder accounted for 59.7 wt % of that of the binding phase; and
(94) (4) the mixture was spray dried and compacted, and the green compact was subjected to a low-pressure liquid phase sintering at 1450° C. to obtain a WC-10% (Ni—Ni.sub.3Al—Y) hard alloy, i.e., WC-10% (Ni—Ni.sub.3Al—Y).
Comparative Example 6
(95) In Comparative Example 6, the contents of Ni.sub.3Al, Y and Ni as a binding phase account for 10% of the total content of a hard phase and the binding phase, and WC powder has a particle size of 0.6 μm.
(96) Comparative Example 6 provides a hard alloy, a preparation method of which is as follows:
(97) (1) Ni.sub.3Al powder, an anhydrous yttrium nitrate alcoholic solution, NbC powder, WC powder and Ni powder were wet milled again for 18 h to obtain a mixture; wherein the total amount of the WC powder accounted for 70 wt % of that of the hard phase, the amount of the added NbC powder accounted for 30 wt % of that of the hard phase, the amount of the added Ni.sub.3Al powder accounted for 30 wt % of that of the binding phase, the amount of yttrium in the anhydrous yttrium nitrate alcoholic solution added accounted for 0.1 wt % of that of the binding phase, and the amount of the added Ni powder accounted for 69.9 wt % of that of the binding phase; and
(98) (2) the mixture was spray dried and compacted, and the green compact was subjected to a low-pressure liquid phase sintering at 1450° C. to obtain a WC—NbC—(Ni—Ni.sub.3Al—Y) hard alloy.
(99) A test method of the high-temperature oxidation resistance at 1000° C./2h: a sample adopted has a diameter of 50 mm and a height of 5 mm. The surface of the sample is ground flat and polished, and placed in a common heat treatment furnace for an oxidation experiment. That is, under the condition of air admission, the sample is heated to 1000° C. and maintained for 2 h, the mass of the sample before and after oxidation is weighed with a balance (accuracy of 1/10,000 g), and the mass increment per unit area is used to characterize the oxidation condition. The smaller the increment is, the better the high-temperature oxidation resistance of the sample is.
(100) A test method of the high-temperature bending strength: test is carried out at 25° C., 500° C. and 800° C. respectively, according to the national standard “GB/T3851-2015”.
(101) A test method of the room-temperature fracture toughness:, test is carried out according to the national standard “JB T 12616-2016 Inspection Methods of Fracture Toughness for Hardmetals Tool Base Material”.
(102)
(103) Comparative Example 2;
(104) Example 5 of the present invention and Comparative Examples 4 and 5; and
(105) It can be obviously seen from
(106) Furthermore, the room-temperature fracture toughness and the high-temperature bending strength of the hard alloys obtained in Example 4 and Comparative Example 6 are detected through the above methods and compared. The results show that both the fracture toughness and the high-temperature bending strength of the rare earth hard alloy prepared in Example 4 are superior to those of Comparative Example 6.
(107) It is to be noted that, the aforementioned examples are intended to explain the present invention only and do not constitute any limitation to the present invention. The invention is described with reference to typical examples, but it is to be understood that the words used therein are descriptive and explanatory rather than restrictive. The invention may be modified within the scope of the claims of the invention as specified, and may be revised without departing from the scope and spirit of the invention. Although the invention described therein relates to specific methods, materials and examples, it is not intended that the invention is limited to the particular examples disclosed therein; rather, the invention can be extended to all other methods and applications having the same function.