Nano-sized MgO powders were synthesized via the precipitation method with Na2CO3 and MgCl2· 6H2O as the reactants. The effects of doping of chloride ions on the synthesis and sintering of MgO powders were investigated. Doping of chloride ions led to the formation of precursor powders with main constituents of basic magnesium carbonate and magnesium normal carbonate. MgO powders with a primary crystalline size of 40nm were obtained by calcining the precursor powders at 900℃ for 4h. The powders obtained from the doped precursors showed improved sinterability. It was found that doping of chloride ions could enhance the densifica-tion and grain growth of MgO during sintering. Sintered bodies with a relative density of 96.4% were obtained for the powders doped with 5mol% chloride ions by sintering at 1200℃ for 3h, whereas only 52. 4% was ob-tained for the samples un-doped under identical sintering conditions.%以无水碳酸钠和六水合氯化镁为原料,采用沉淀法,制备了纳米MgO粉体,重点考察了氯离子在粉体合成中的影响.研究表明,在沉淀工艺中掺入氯离子,可以改变先驱物的物相组成,获得以碱式碳酸镁和水合碳酸镁为主要组分的先驱物,在900℃煅烧后可以获得一次颗粒尺寸为40nm的MgO粉体.粉体制备中加入氯离子,烧结时具有促进氧化镁烧结致密化和晶粒长大的作用,同时还有利于获得晶粒尺寸分布均匀的显微组织.掺杂5%(质量分数)氯离子的粉体在空气气氛1200℃烧结3h,样品密度为96.4%,而相同条件下未掺杂氯离子样品的密度只有52.4%.
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