SmBO_3粉体的颗粒度对其反射性能的影响

Effects of granularity on the reflectivity of SmBO_3 powders

分析了SmBO3颗粒度对粉体散射作用和吸收作用的影响。激光防护功能填料对激光的散射作用主要考虑米氏散射;在激光防护功能填料质量一定的条件下,粒径越小,粒子数就越多,粒子对光的吸收截面越大,吸收系数也就越大。对于SmBO3激光防护功能填料,折射率n=1.95时,激光波长为1.06μm,散射面积比Q(λ)随粒径参数χ的函数变化关系图可以得到当χ=1.771时,SmBO3的散射面积比最大,此时2πr/λ=1.771,即r≈298nm。所以当颗粒尺寸大约在600nm左右时,SmBO3微粒的散射消光作用最强。在1.05～1.15μm波长范围内,随着SmBO3颗粒的长大,粉体对1.06μm波长处的光的反射率有所降低,并在颗粒大小为587nm左右时达到最低值,约为0.5%。而当颗粒尺寸进一步长大时,SmBO3粉体对1.06μm波长处的光的反射率值又有所提高。当颗粒大小达到1μm左右时,SmBO3粉体对1.06μm波长处的光的反射率约0.6%。这与理论计算得出的具有最佳散射消光的SmBO3粉末的颗粒尺寸为600nm左右相一致,符合理论计算结果。激光测试也显示600nm左右的SmBO3颗粒对1.06μm激光的反射率最低,符合理论计算结果。

Effects of granularity of SmBO3 powders on the scattering and absorption were analyzed. Mie scattering was mainly considerd for laser protective functional filler against laser scattering. If the mass of laser protective functional filler was constant, the particle size was smaller, particle counts was more, light absorption cross section and the absorption coefficient were greater. For SmBO3 laser protective functional filler, refractive index n=1. 95, the laser wavelength was 1. 06μm. It can be obtained that scattering area ratio of was the largest when χ was 1. 771 from the diagram of scattering area ratio Q（λ） as a function of particle size parameter χ. At this time, 2πr/λ was 1. 771 and so r was about 298nm. Therefore, when the particle size was about 600nm, the scattering extinction of SmBO3 was the strongest. In the wavelength range of 1. 05 to 1. 15μm, with the particles growing up, the reflectivity at 1. 06μm decreased, and it reached the minimum value of about 0. 5% as the particle size was about 587nm. As the particle size further grew up, reflectivity values increased. When the particle size was about 1μm, the reflectivity reached about 0. 6%. It was consistent with the result of theoretical calculation that the best scattering extinction particle size of SmBO3 powders was about 600nm. 1. 06μm laser direct tests showed that the reflectivity was the lowest when the granularity of SmBO3 powders was 600 nm. It was also consistent with the result of theoretical calculation.