The pure Ti castings were produced with high temperature phosphate investment materials containing 20%

30% and 40% ZrO2

respectively

by investment casting

and compared pure Ti castings was produced with special MT-3 investment materials. The optimized proportion between ZrO2 content and phosphate investment materials was presented through examining the properties of Ti castings by the XRD（X-ray diffraction） and SEM（scanning electron microscope）

EDS（energy dispersive spectrometer） . The results show that there exists a lot of porosity in castings produced with high temperature phosphate investment materials containing 20% ZrO2

and porosity rate exhibits significant difference with the compared castings

while significant difference in porosity rates in the casting produced with investment materials containing 30% and 40% ZrO2 can not be observed with the compared castings. In addition

the reactive layer on the castings produced with 20% ZrO2 is the thickest

and then castings produced with 30% and 40% ZrO2

and the reactive layer of the casting produced with the special MT-3 investment casting is the thinnest. The phosphate investment casting with 30% ZrO2 exhibits acceptable properties.