采用M80弹(7.62 mm×51 mm NATO)分别对常温和高温(55℃)下的防弹插板进行实弹射击试验,以研究高温环境对防弹插板抗弹性能的影响。通过分析试验时防弹插板弹击瞬间凹陷值,同时结合聚氨酯树脂的剥离强度、超高分子量聚乙烯纤维层压...采用M80弹(7.62 mm×51 mm NATO)分别对常温和高温(55℃)下的防弹插板进行实弹射击试验,以研究高温环境对防弹插板抗弹性能的影响。通过分析试验时防弹插板弹击瞬间凹陷值,同时结合聚氨酯树脂的剥离强度、超高分子量聚乙烯纤维层压板剥离强度和弯曲强度的测试结果对高温下抗弹性能变化原因进行了研究。结果表明:高温下防弹插板抗弹性能明显下降,相对于常温下每发弹的弹击瞬间凹陷值增加了2~5 mm。其主要原因是超高分子量聚乙烯纤维层压板在高温下抵抗变形的能力发生明显下降,从而导致防弹插板的弹击瞬间凹陷值增大。展开更多
The effects of particle size,gradation and solid loading of silicon nitride (Si_(3)N_(4)) on the rheological behavior and curing properties of ceramic slurry are studied by stereolithography (SLA).The results show tha...The effects of particle size,gradation and solid loading of silicon nitride (Si_(3)N_(4)) on the rheological behavior and curing properties of ceramic slurry are studied by stereolithography (SLA).The results show that the particle size of Si_(3)N_(4) powder has a signif icant influence on the rheological properties and stability of the slurry.When m_(D50=1.3μm):m_(D50=2.3μm)=3:7,the slurry viscosity is low and the sedimentation is slow.The most important thing is that with the increase of the solid loading of the slurry,the viscosity of the slurry increases,the stability becomes higher,and the curing thickness decreases.The curing thickness of Si_(3)N_(4) ceramic slurry with solid loading of 50 vol% can reach nearly 50μm.The above results finally show that the process optimizes the formulation of the slurry in rheological and curing properties.展开更多
SiC粉体表面SiO_(2)氧化层对其浆料粘度、流变性产生的影响一直是胶态成型技术关注的问题。采用NaOH、KOH和Na_(2)CO_(3)三种不同强度的碱性溶液对SiC粉体进行处理,考察碱性溶液对SiO_(2)氧化层的活化以及对粉体分散稳定性产生的影响。Z...SiC粉体表面SiO_(2)氧化层对其浆料粘度、流变性产生的影响一直是胶态成型技术关注的问题。采用NaOH、KOH和Na_(2)CO_(3)三种不同强度的碱性溶液对SiC粉体进行处理,考察碱性溶液对SiO_(2)氧化层的活化以及对粉体分散稳定性产生的影响。Zeta电位测试表明,中性时Na_(2)CO_(3)处理后粉体表面的电位绝对值比酸洗粉体提高了16.8 mV,pH值为10时达到67.8 m V。所制备固相含量为35 vol%的浆料,粘度低、稳定性好。因此,适度活化SiC粉体表面氧化层有助于改善浆料的流变性能。展开更多
文摘采用M80弹(7.62 mm×51 mm NATO)分别对常温和高温(55℃)下的防弹插板进行实弹射击试验,以研究高温环境对防弹插板抗弹性能的影响。通过分析试验时防弹插板弹击瞬间凹陷值,同时结合聚氨酯树脂的剥离强度、超高分子量聚乙烯纤维层压板剥离强度和弯曲强度的测试结果对高温下抗弹性能变化原因进行了研究。结果表明:高温下防弹插板抗弹性能明显下降,相对于常温下每发弹的弹击瞬间凹陷值增加了2~5 mm。其主要原因是超高分子量聚乙烯纤维层压板在高温下抵抗变形的能力发生明显下降,从而导致防弹插板的弹击瞬间凹陷值增大。
基金Funded by National Natural Science Foundation of China (No.43200021)。
文摘The effects of particle size,gradation and solid loading of silicon nitride (Si_(3)N_(4)) on the rheological behavior and curing properties of ceramic slurry are studied by stereolithography (SLA).The results show that the particle size of Si_(3)N_(4) powder has a signif icant influence on the rheological properties and stability of the slurry.When m_(D50=1.3μm):m_(D50=2.3μm)=3:7,the slurry viscosity is low and the sedimentation is slow.The most important thing is that with the increase of the solid loading of the slurry,the viscosity of the slurry increases,the stability becomes higher,and the curing thickness decreases.The curing thickness of Si_(3)N_(4) ceramic slurry with solid loading of 50 vol% can reach nearly 50μm.The above results finally show that the process optimizes the formulation of the slurry in rheological and curing properties.
文摘SiC粉体表面SiO_(2)氧化层对其浆料粘度、流变性产生的影响一直是胶态成型技术关注的问题。采用NaOH、KOH和Na_(2)CO_(3)三种不同强度的碱性溶液对SiC粉体进行处理,考察碱性溶液对SiO_(2)氧化层的活化以及对粉体分散稳定性产生的影响。Zeta电位测试表明,中性时Na_(2)CO_(3)处理后粉体表面的电位绝对值比酸洗粉体提高了16.8 mV,pH值为10时达到67.8 m V。所制备固相含量为35 vol%的浆料,粘度低、稳定性好。因此,适度活化SiC粉体表面氧化层有助于改善浆料的流变性能。
