氧化时间对纯钛表面微弧氧化涂层微孔参数的影响

在含钙磷的硅酸盐电解液体系中,采用微弧氧化技术在纯钛表面制备多孔涂层,分析不同氧化时间(3,6,9,12,15 min)对涂层孔径大小、孔隙率等微孔参数的影响.通过扫描电镜(SEM)获取涂层表面形貌的原始图像,采用MATLAB图像处理技术实现涂层微孔参数的自动分析与定量表征.结果表明:处理后图像中的大小微孔可以被清晰识别;当氧化时间为3 min时,孔径小于1μm的微孔数量最多,大约占总数的4/5,涂层表面孔隙率为10.5%;随着时间的延长,微孔总数明显减少,孔径大于4μm的微孔持续增加,涂层孔隙率不断增大;当处理时间延长到15 min时,出现8μm及以上的大孔,表面孔隙率增长至15.0%左右.

微孔膜包装内外气体交换的理论研究

为有效地提高包装膜的透气率,基于原包装膜而进行后加工制孔是近年来采用的主要技术手段之一。探讨了该类型微孔膜的透气机理,基于气体的渗透与粘性流动理论,建立微孔膜硬质盒包装、袋包装内外气体交换模型。理论分析了包装型式、微孔参数对包装内气份变化的影响。结果表明:设置微孔可显著地提高包装内外气体的交换速率;包装型式对包装内气份的变化有影响但不显著;包装膜孔隙率、微孔孔径显著地影响包装内气份变化速率,且孔径大小对包装内气份变化的影响更为显著。

A Model of Steady-State Convective Combustion of Micropore Propellants

Aim To develop a physical and mathematical model related to micropore para- meters of steady-state convective combustion of micropore propellants(MPP). Methods The micropore parameters were measured by WXT-88 mage analysis apparatus and the convective combustion characteristic of MPP was measured by a large volume closed bomb, respectively. Rasults Statistical physical model of burning in the micropore and granular burning were developed. The burning rate equation of steady-state convective combustion of MPP was obtained. Conclusions This model correlates the convective burning rate with micropores para- meters for the first time,and the calculating values of convective burning rate are in agreement with test results.The model also can be used to estimate the effects of microporous parame- ters, basic mass burning rate, MPP density and pressure in combustion chamber on the convective combustion characteristics of MPP.