The metal ceramic powder with a particle size of 15-45 .Math.m and suitable for thermal spraying is prepared through a combination of mechanical ball milling, spray granulation, and vacuum sintering. The metal ceramic powder is sprayed on a surface of a steel substrate adopting the high velocity oxygen fuel (HVOF) technology with oxygen-propane as fuel and taking oxygen as a combustion improver, propane as fuel, nitrogen as powder feeding carrier gas, and air as a cooling medium to prepare and form the NiCrBSi—ZrB2 composite coating. The present disclosure solves the problem that ZrB.sub.2 ceramic is difficult to compact during sintering and improves powder bonding strength and fluidity. The preparation method is simple, has advantages of high coating deposition efficiency and convenient equipment operation, and is cost-effective. The preparation method can improve thermal corrosion resistance and high-temperature wear resistance of a surface of boiler, and prolonging lifetime of the boiler.

The metal ceramic powder with a particle size of 15-45 .Math.m and suitable for thermal spraying is prepared through a combination of mechanical ball milling, spray granulation, and vacuum sintering. The metal ceramic powder is sprayed on a surface of a steel substrate adopting the high velocity oxygen fuel (HVOF) technology with oxygen-propane as fuel and taking oxygen as a combustion improver, propane as fuel, nitrogen as powder feeding carrier gas, and air as a cooling medium to prepare and form the NiCrBSi—ZrB2 composite coating. The present disclosure solves the problem that ZrB.sub.2 ceramic is difficult to compact during sintering and improves powder bonding strength and fluidity. The preparation method is simple, has advantages of high coating deposition efficiency and convenient equipment operation, and is cost-effective. The preparation method can improve thermal corrosion resistance and high-temperature wear resistance of a surface of boiler, and prolonging lifetime of the boiler.

The present disclosure provides an aluminum alloy workpiece and a preparation method thereof. By optimizing a composition of the aluminum alloy workpiece, the aluminum alloy workpiece can be prepared by laser powder bed fusion (LPBF) in the preparation method, thereby forming a target metallographic phase. The preparation method overcomes the problem that the composition of a high temperature-resistant and high-strength aluminum alloy designed based on the traditional casting and forging process cannot be matched with the LPBF, and makes full use of rapid cooling of the LPBF to prepare an aluminum alloy composition of a target crystal phase. The preparation method combines the aluminum alloy composition with the LPBF to achieve mutual promotion, thereby forming a target workpiece, such that an aluminum alloy with high strength and toughness at room temperature/high temperature can be prepared by the LPBF.

Provided is a stainless steel powder composition, which comprises Cr, Cu, Mn, Mo, Ni and Fe; wherein, based on a total weight of the stainless steel powder composition, a content of Cr is 20 wt% to 24 wt%, and a content of Cu is more than 0 wt% and less than or equal to 0.5 wt%, a content of Mn is more than 0 wt% and less than or equal to 2 wt%, a content of Mo is 2.25 wt% to 3 wt% and a content of Ni is 10 wt% to 15 wt%. When applying the stainless steel powder composition of the present invention to laser additive manufacturing (LAM), the produced stainless steel workpiece has enhanced tensile strength, thereby expanding the follow-up applications and increasing the commercial value.

A method to achieve full densification and grain size control for sintering metal materials, wherein raw material powder is deagglomerated to obtain deagglomerated powder with dispersion. The deagglomerated powder is granulated by spray granulation. The granulated particles are processed by high-pressure die pressing and cold isostatic pressing. The powder compact is sintered by two-step pressureless sintering. The first step is to heat up the powder compact to a higher temperature and hold for a short time to obtain 75-85% theoretical density; the second step is to cool down powder compact to a lower temperature and hold for a long time. The two-step sintering can decrease the sintering temperature, so that the powder compact can be densified at a lower temperature. Thus, the obtained refractory metal product is densified, with ultrafine grains, uniform grain size distribution, and outstanding mechanical properties.

A method to achieve full densification and grain size control for sintering metal materials, wherein raw material powder is deagglomerated to obtain deagglomerated powder with dispersion. The deagglomerated powder is granulated by spray granulation. The granulated particles are processed by high-pressure die pressing and cold isostatic pressing. The powder compact is sintered by two-step pressureless sintering. The first step is to heat up the powder compact to a higher temperature and hold for a short time to obtain 75-85% theoretical density; the second step is to cool down powder compact to a lower temperature and hold for a long time. The two-step sintering can decrease the sintering temperature, so that the powder compact can be densified at a lower temperature. Thus, the obtained refractory metal product is densified, with ultrafine grains, uniform grain size distribution, and outstanding mechanical properties.

A method for preparing a rare earth aluminum alloy powder applicable for additive manufacturing includes: heating and melting aluminum ingots into an aluminum melt; adding required alloy elements to the aluminum melt to obtain an alloy melt in which the alloy elements are present in the following preset percentages by weight: 1.00% to 10.00% of Ce, 0.05% to 8.00% of Mg, 0.10% to 7.50% of Y, 0.10% to 2.50% of Zr, less than 0.1% of impurities, and the balance aluminum; leading out the alloy melt through a fluid guiding pipe, and impacting the alloy melt with a high-pressure gas flow so that the alloy melt is atomized into fine droplets under an action of surface tension, and solidified into spherical alloy powder; and collecting the spherical alloy powder in a vacuum collector, and screening and drying the spherical alloy powder to obtain the rare earth aluminum alloy powder.

A method for preparing a rare earth aluminum alloy powder applicable for additive manufacturing includes: heating and melting aluminum ingots into an aluminum melt; adding required alloy elements to the aluminum melt to obtain an alloy melt in which the alloy elements are present in the following preset percentages by weight: 1.00% to 10.00% of Ce, 0.05% to 8.00% of Mg, 0.10% to 7.50% of Y, 0.10% to 2.50% of Zr, less than 0.1% of impurities, and the balance aluminum; leading out the alloy melt through a fluid guiding pipe, and impacting the alloy melt with a high-pressure gas flow so that the alloy melt is atomized into fine droplets under an action of surface tension, and solidified into spherical alloy powder; and collecting the spherical alloy powder in a vacuum collector, and screening and drying the spherical alloy powder to obtain the rare earth aluminum alloy powder.

The invention includes apparatus and methods for instantiating precious metals in a nanoporous carbon powder.

The invention includes apparatus and methods for instantiating precious metals in a nanoporous carbon powder.