CAJ | 학술논문

在熔体发泡法工艺中，发泡剂的分解速度和浸润性直接影响泡沫金属的孔结构和孔隙率。为减缓泡沫镁发泡剂 CaCO3的发泡速度并提高与镁熔体的浸润性，采用非均匀形核法，以硅酸钠为原料，盐酸为酸化剂，在CaCO3表面包覆SiO2钝化膜。采用TGA?DTA、XRD、SEM等方法对包覆后CaCO3的热稳定性和包覆层的微观结构进行分析。结果表明：包覆后的CaCO3分解温度提高；包覆层中的SiO2为无定形态；在CaCO3颗粒表面形成网络状结构。对比实验表明：包覆后的CaCO3发泡速度平稳。同时，采用合金化阻燃工艺在无气体保护条件下制备出较大尺寸的泡沫镁试样，并且试样孔径细小，孔结构均匀，孔隙率在60%?70%。
재용체발포법공예중，발포제적분해속도화침윤성직접영향포말금속적공결구화공극솔。위감완포말미발포제 CaCO3적발포속도병제고여미용체적침윤성，채용비균균형핵법，이규산납위원료，염산위산화제，재CaCO3표면포복SiO2둔화막。채용TGA?DTA、XRD、SEM등방법대포복후CaCO3적열은정성화포복층적미관결구진행분석。결과표명：포복후적CaCO3분해온도제고；포복층중적SiO2위무정형태；재CaCO3과립표면형성망락상결구。대비실험표명：포복후적CaCO3발포속도평은。동시，채용합금화조연공예재무기체보호조건하제비출교대척촌적포말미시양，병차시양공경세소，공결구균균，공극솔재60%?70%。
In melt foaming method, the thermal stability and foaming speed of blowing agent significantly affect the pore structure, pore size and porosity of metal foams. To retard the foaming speed and increase thermal stability, Na2O·nSiO2 and dilute hydrochloric acid were used to coat SiO2 passive layer on the surface of CaCO3 which is the blowing agent of Mg foams. Thermal stability and microstructure of the SiO2 passive layer were studied by thermo gravimetric analyzer?differential thermal analysis (TGA?DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that the thermal stability of coated CaCO3 is improved. The SiO2 layer is amorphous with reticular structure. Contrasting experiments reveal that the coated CaCO3 can foam placidly. Moreover, large size and homogeneous Mg foams were prepared without protective gas with the ignition-proof by alloying. And the porosity of the Mg foams is 60%?70%.