共查询到15条相似文献,搜索用时 78 毫秒
1.
2.
3.
4.
用氧化铬 (Cr2 O3)作补偿掺杂剂、LEC法生长的GaAs窗口晶体 ,容易满足高阻补偿条件 ,碳、硅两种主要的残余杂质得到有效抑制 ,获得低自由载流子光吸收的优质GaAs红外激光出口材料。补偿掺杂剂氧化铬 (Cr2 O3)剂量为 99 9999%Ga和 99 9999%As量的优选范围是0 0 1%~ 0 0 4% (质量分数 )。室温下的自由载流子浓度低于 5× 10 6 cm- 3,对光吸收系数的贡献可以忽略。轻掺氧化铬高阻GaAs晶体具有良好的红外透射特性 ;10 6μm处激光量热法测量的红外光吸收系数约为 1 4× 10 - 3cm- 1 。 相似文献
5.
IF钢的出现对连续退火工艺生产了巨大影响。详细介绍了IF钢的特点及其连续退火工艺,并对IF钢连续退火产品与普碳钢连续退火产品的性能及退火工艺进行了比较。 相似文献
6.
超万瓦高功率GaAs红外激光窗口材料的研制 总被引:1,自引:0,他引:1
采用掺杂、合成、高压炉内一次直接完成拉晶的方法,结合铬、氧双掺的补偿掺杂新工艺和热处理工艺,稳定批量研制超万瓦GaAs红外激光窗口材料。该材料具有吸收系数低、机械强度高、热破裂品质因素和光畸变品质因素高等特点,成功地应用于12kW连续二氧化碳强激光器上连续输出8h而不发生破裂。 相似文献
7.
8.
9.
10.
为了系统研究临界区退火和全奥氏体区退火对中锰钢性能的影响,为中锰钢的实际应用提供理论基础,在650~900 ℃范围内系统研究了冷轧中锰钢的显微组织和力学性能,并通过断口形貌观察分析了试验钢的断裂特性。结果表明,试验钢在临界区退火的综合力学性能明显优于全奥氏体区退火。650~750 ℃退火时,抗拉强度在1 000 MPa左右,强塑积超过30 GPa·%,发生韧性断裂,宏观上可以观察到明显的层状裂纹,微观下为大量韧窝;在800~900 ℃退火时,抗拉强度在743~1 154 MPa范围内波动较大,强塑积不足10 GPa·%,断口平整,发生脆性沿晶断裂;退火温度为650 ℃时,组织为片层状和等轴状的奥氏体、铁素体双相及大量渗碳体;随着退火温度的升高,渗碳体逐渐溶解消失,等轴状组织所占体积分数明显增加,奥氏体体积分数也不断增加,在750 ℃时达到52.2%;退火温度为800 ℃时,有马氏体产生,奥氏体体积分数下降;退火温度为900 ℃时,组织基本为马氏体,残留奥氏体体积分数仅为14.6%。 相似文献
11.
Increasing density is one of the important factors for producing high quality powder metallurgy (PM) parts, which has beneficial effect on mechanical properties. One of the common techniques for achieving this goal is double compacting, which seems to be a potentially attractive method in PM route, also for Cr-Mo alloyed-steels. The objective of this research was to investigate the effect of first compacting pressure and intermediate annealing temperature on attaining higher densities and minimum interconnected porosity for Cr-Mo pre-alloyed steel. The effect of mentioned parameters was studied by measuring density, transverse rupture strength and macrohardness of repressed samples. The results show that for each first compacting pressure, the density range of repressed samples increases with the increasing annealing temperature up to a certain limit, due to C dissolution which causes free porosity and further densification. Annealing temperatures higher than optimum one should be avoided, since too much carbon dissolution results in harder and less deformable compacts. On the other hand, with regard to repressed density and other resulted properties, the amount of first compacting pressure offers considerable advantage in obtaining higher level of density and consequently improved mechanical properties. 相似文献
12.
13.
14.
15.
在正交试验确定的工艺参数条件下,改进工艺制备出具有氧化锆包覆方镁石显微结构的镁锆砖.在此微观结构中,方镁石和氧化锆直接结合,两相邻方镁石晶粒被氧化锆间隔,方镁石晶粒被氧化锆包裹,方镁石晶内存在封闭小气孔和氧化锆晶粒.由于方镁石被氧化锆包裹中存在氧化锆相变,相变微裂纹吸收断裂能起增韧的作用;同时,方镁石晶粒内的微气孔能缓解热应力,使镁锆材料的抗热震性能和高温强度均得以改善.方镁石晶粒内的细小氧化锆晶粒具有钉扎效应,能减少和阻止镁锆砖的高温蠕变滑移,提高了材料的高温抗折性能. 相似文献