摘要 |
1,274,732. Strengthening glass. GLAVERBEL. 25 June, 1969 [12 Sept., 1968], No. 32150/69. Heading C1M. Compressive surface stresses are set up or increased in at least part of a body of glass, glass-ceramic or ceramic by a chemical tempering treatment using a liquid medium, in which the liquid medium is continuously supplied to and streams along the body. The liquid medium may be supplied from jets, and body and jets may be in reciprocating relative motion. The liquid may be, e.g. molten KNO 3 or a mixture of LiNO 3 (2 mol. per cent) and NaNO 3 (98 mol. per cent), and may be regenerated and recycled after use. Differential tempering may be carried out by varying the flow rates of the jets or by varying the liquid used. The liquid may be streamed along the body in the presence of a gas which influences ion diffusion into the body, e.g. H 2 O, CO 2 , SO 2 , SO 3 or halogen. The ion diffusion may be assisted by an electric field, which may be alternating. Suitable apparatus is disclosed. Specification 1,274,733 is referred to. |