水热法生长红宝石技术

Hydrothermal Growth Technique of Ruby

利用水热法合成出数粒块状红宝石晶体，其颜色为略带玫瑰的鲜红色，最大尺寸为５０ｍｍ×１７ｍｍ×１５ｍｍ。籽晶切向以（２２４＾－３）为主、以Ｃｒ２Ｏ３为致色主要化合物。水热红宝石的晶体结构、化学成分及其它宝石学特点均同天红宝石相似，但水热法合成红宝石Ｃｒ２Ｏ３含量明显偏低于天然红宝石。此外Ｖ２Ｏ５的含量也较低。红宝石的水热生长试验在密封贵金属衬管中进行。使用自行设计制造的反应腔尺寸为Φ３８ｍｍ×７００ｍｍ的高压釜及温差井式电阻炉；釜内温度５００℃～６００℃，晶体生长区（低温区）与溶解区（高温区）的温差３０℃～８０℃；釜内压力１５００ａｔｍ～２０００ａｔｍ；釜内开孔档板使用贵金属，开孔率５％～２５％。介质溶液为钾钠的复杂碱性混合溶液，并掺入一定量的矿化离子（矿化剂）。

Synthetic ruby crystals with pinkish red color are produced by hydrothermal method. The maximum size of crystals with seed slice cut in the direction of n (2243 ) are 50 mm×17 mm×15 mm. Chromium oxide is dominant color causing compound. Crystal structure, chemical composition and other gemological properties of hydrothermal rubies are similar to that of natural rubies, Cr 2O 3 percentage is clearly lower than that of natural rubies as for the V 2O 5 is a little lower than the natural one′s.An experiment on hydrothermal growth are in process in a sealed tube with a precious metal liner.In a self made reaction chamber,an autoclave with a size 38 mm×700 mm and a thermal resister furnace.The temperature range in the autoclave is 500℃ to 600℃,the temperature difference between crystal growth zone(Low temperature zone) and dissolving zone (High temperature zone) is 30℃ to 80℃,Pressure ranges from 1 500 atm to 2000 atm,in the autoclave a precious metal porous baffle with a porosity of 5% to 25%.The medium solution is a complex alkaline solution of sodium carbonates and potassium carbonates containing some necessary mineralizing ions.