Process for producing crystals

US4678535A · kind A · utility

Assignee

• Avl Gesellschaft fur Verbrennungskraftmaschinen und Messtechnik m.b.H. Prof.Dr.Dr.h.c. Hans List · AT

Inventors

• Hermenegild Mang · Graz, AT
• Günter Engel · Leibnitz, AT

Key dates

• Filing date: Jun 13, 1985
• Grant date: Jul 7, 1987
• Expiry date: Jun 13, 2005

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C30B29/14
• WIPO field: Surface technology, coating
• WIPO sector: Chemistry

Abstract

In a process for producing crystals in crystallographic point group 32 and corresponding to the comprehensive chemical formula APO.sub.4, wherein symbol A is a chemical element taken from the group Al and Ga, P is phosphorus and O is oxygen, from heated solutions of salts of group A in phosphorus acid, the application of acid concentrations within the range of 12.5 to 20 mol/l, solution temperatures within the range of 110.degree. to 190.degree. C. and total pressures within the range of prevailing static vapour pressure to 2.5 bar provides a simple, safe and cost-effective method of producing perfect, flawless crystals.