This research article aims to study of the atomizer nozzle pattern in the gas atomization process. The production of metal powder by using a gas atomization process. It is the most popular process. This process is used in various industry and engineering application. However there is lack of information on the production of various precious metal powders in the jewelry manufacturing industry both in the country and abroad. For this reasons the research team is interested in applying this process for the Thai jewelry manufacturing industry. Currently the jewelry industry is in a transitional period of manufacturing technology with an increased focus on powder metallurgy technology. The production of metal powder by using a gas atomization process consisting of the following 3 steps: melting making of atomized molten metal cooling and solidifying for solid particles under a controlled gas atmosphere. Factors affecting particle shape particle size and particle size distribution are consisting of inert gas type molten metal temperature and the configuration or pattern of the nozzle that are different characteristics. The results can be concluded that Close-Coupled Nozzle is the most suitable nozzle for production due to the highest productivity providing the smallest particle size and spherical granular shape. The information from this study will be useful for the Thai jewelry manufacturing industry.

The research involved the characterization of the properties of silver alloys -bearing copper and zinc. The alloys composed of 58.4% silver 20.85-41.76% copper and 0-20.83% zinc respectively. When comparing the characteristics of this alloy and sterling silver 925 the alloy specimen had mechanical properties better than the sterling silver 925. The alloy tests presenting the mechanical values of the hardness shear bond strength elasticity of the specimen were in a range of 54.6-95.3 HV1 209.5-379.3 MPa. 100.6-193.8 MPa. and 32.1-51.7% respectively. While the mechanical values of sterling silver 925 were 52.8 HV1 193.5MPa. 96.0 MPa. and 29.8% respectively. Besides these the microstructure of the alloy specimen showed the dendrite structure. We found that this structure decreased when the concentration copper in the specimen increased. After adding zinc into the alloys the high amount of zinc caused the zinc-rich (alpha) phase changed to Eutectic phase together with the significantly increased area of alpha phase. These effects therefore brought up the better various mechanical properties of the alloys. At the same time the another test specimen composed 58.67% Ag 39.20% Cu and 2.14% zinc. The color level of this specimen was close typically to the sterling silver 925 with the difference of Da at 0.236 and Db only at 5.268. Additionally the higher copper concentration in the alloy provided a value tentatively increased but b value decreased. However more remarkable results were that the zinc showed opposite effects from the copper.