Effect of silica additions on the structure, phase transformation, and compressive strength on sintered Perlis dolomite mineral

Abstract

Natural dolomite sedimentary rocks, which can be found in abundance in Perlis, are carbonate minerals rich with calcium and magnesium elements. Both elements are commonly found in bioceramic materials, particularly for hard tissue implants. Even though raw Perlis dolomite powder has other various elemental compositions, it is deficient in important components, such as silica and phosphate, which are commonly used as glass network formers, therefore limiting its potential application as bioceramic materials. This study examines the effects of different percentages of silica powder addition on sintered Perlis dolomite, and the changes in its structure, phase transformation, and compressive strength were analyzed. Perlis dolomite with different ratios of silica (25–45 wt. %) was ball milled, compacted into pellets, and sintered at 1250°C for 4 hours. The results showed that at lower silica content
(≤30 wt. %), the MgO phase becomes the dominant phase. However, increasing silica content promotes the formation of akermanite, monticellite, and merwinite phases, although the merwinite phase disappears at 45 wt. %. Higher silica content in dolomite enhances phase stability by increasing the akermanite phase, reduces shrinkage, and increases densification of the sintered samples, which contributes to the improvement in compressive strength.