| 摘要 |
1279156 Foamed silica G M MANSFIELD 19 June 1969 [19 June 1968] 31119/69 Heading C1M [Also in Division C7] A solid foamed product of a fusible material e.g. silica is made by (1) forming a molten mixture of the fusible material and a volatilizable material under pressure conditions at which the volatilizable material has a volatilization temperature which is greater than the fusion temperature of the fusible material but less than the volatilization temperature of the fusible material, and (2) adjusting the conditions of heat and/or pressure in the mixture so as to volatilize the volatilizable material, the heat required for volatilization being supplied at least in part by the latent heat of fusion of the fusible material whereby the volatilization causes chilling and solidification of the fusible material in the vicinity of volatilization. The molten mixture may be formed at atmospheric pressure and then the pressure reduced to cause volatilization. Alternatively, the mixture may be formed in a pressurized container, and then the pressure released to cause volatilization. |
