41. Yttria is used as a sintering additive in the production of porous silicon nitride. 42. Sintering involves consolidating a material by heating, but to temperatures below the melting point.43. Part of the firing process includes sintering . 44. During the sintering process, the nickel diffuses into the tungsten, producing an alloy. 45. The study of sintering in metallurgy powder-related processes is known as powder metallurgy. 46. The estimated sintering temperature was 2000 �C. 47. In the United States, sintering was first patented by Duval d Adrian in 1922. 48. Magnesium phosphates and calcium phosphates are the examples which have been processed through microwave sintering technique 49. Especially rare earth metals have been shown to reduce sintering of metal catalysts when alloyed. 50. These alternative methods, however, still require careful sintering to produce a quality product.
