Method for forming powder particles and a product

Abstract

The invention relates to a method for forming powder particles, wherein the method comprises feeding a start material mixture including more than one constituents in the form of granules into a reactor comprising a reaction zone and a heat source, performing thermal synthesis in the reaction zone in which the start material mixture is moved and the constituents of the start material mixture react in the presence of heat so that the reaction is started by means of heat of the reactor and energy of the start material mixture is released in the form of heat in order to achieve the reaction, and producing powder particles during the reaction. Further, the invention relates to a powder particle product.

Claims

1. A method for forming powder particles, the method comprising: forming granules from a start material mixture including more than one constituent by granulating the start material mixture to the granules which comprise at least two constituents, the size of which is below 0.5 mm, feeding the granules into a reaction zone of the reactor in which a thermal process is performed and the reactor comprises a flame-based heating unit, performing the thermal process, as an in-situ synthesis in the reaction zone in which the granules are moved and the constituents of the granules react in the presence of heat to form composite powder particles, and the reaction is started by means of heat of the flame-based heating unit and heat energy is generated by means of the reaction in the reaction zone and is released in order to sustain the reaction between the constituents, and producing directly the composite powder particles, wherein the particle size is below 500 μm and wherein the powder particles are carbide-based composite powder particles, during the reaction in the reaction zone.

2. The method according to claim 1, wherein the start material mixture includes a binder that facilitates the formation of granules during the method, the binder being chosen from the group consisting of carbon, titanium oxide, aluminum oxide, and combinations thereof.

3. The method according to claim 1, wherein the start material mixture is selected from the group consisting of: carbon, titanium, silicon, hafnium, zirconium, tantalum, boron, nitrogen, iron, nickel, cobalt, aluminum, and combinations thereof.

4. The method according to claim 1, wherein the flame-based heating unit is sufficient to produce a processing temperature of at least 1100° C.

5. The method according to claim 1, wherein a high processing temperature of at least 1100° C. and short retention time of less than 5 seconds are used in the reaction zone.

6. The method according to claim 1, wherein the start material mixture is fluidized in the reaction zone.

7. The method according to claim 1, wherein protective gas is used for avoiding oxidation in the reactor.

8. The method according to claim 1, wherein the start material mixture feed, heat of the reactor and processing time are controllable and adjustable in the reactor.

9. The method according to claim 1, wherein the powder particles are oxide metal particles, oxide-carbide particles.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) The accompanying drawings, which are included to provide a further understanding of the invention and constitutes a part of this specification, illustrate some embodiments of the invention and together with the description help to explain the principles of the invention. In the drawings:

(2) FIG. 1 is a flow chart illustration of a method according to one embodiment of the present invention, and

(3) FIG. 2 shows one embodiment of synthesized particles.

EXAMPLES

(4) The invention is described in more detail by the following examples with reference to accompanying drawings.

(5) The description below discloses some embodiments of the invention in such a detail that a person skilled in the art is able to utilize the invention based on the disclosure. Not all steps of the embodiments are discussed in detail, as many of the steps will be obvious for the person skilled in the art based on this specification.

(6) FIG. 1 illustrates a process that may be used to implement a method according to one embodiment of the present invention for forming powder particles product.

Example 1

(7) In this example, powder particles are formed according to a process of FIG. 1.

(8) A start material mixture (1), such as reactive precursor material, comprises at least two different constituents which contain metal, carbon and inorganic constituent. The start material mixture has been granulated. The start material granules are fed into a reactor (2), into the reaction zone, and introduced to a high temperature source (3), such as flame heating unit, where the start material granules (1) are fluidized and where they react and form powder particle product (4) comprising spherical powder particles.

(9) The devices used in this invention are known per se, and therefore they are not described in any more detail in this context.

Example 2

(10) In these tests, powder particles were formed according to a process of the present invention.

(11) TiC-metal particles were formed in-situ TiC-metal synthesis using oxygen-acetylene flame, which was a rapid synthesis for forming carbide based product. Granules of the start material mixture were introduced into the reaction zone, which was flame heating unit, where the flame pyrolysis was performed. The reaction was started with the flame, and the reaction between constituents of the start material mixture was based on an exothermic reaction. Using flame heating unit start material feed and combustion heat and start material retention time in the flame can be adjusted and controlled effectively. Spheroidized, TiC-metal matrix composite powders were able to be done with flame heating setup. Oxidation was avoided by using protective gas like argon.

(12) It was observed that the in-situ exothermic reaction synthesis ensures the strong bond between hard carbide particles and ductile continuous matrix. It was observed that smooth and round TiC-metal particles can be produced in the tests. The synthesized powder morphology is shown in FIG. 2.

(13) The method according to the invention is suitable in different embodiments to be used for forming the most different kinds of powder particles.

(14) The invention and its embodiments are not limited to the examples described above; instead many variations are possible within the scope of the inventive idea defined by the claims.