以酒石酸加入Ba2+、Fe3+離子水溶液中，獲得鋇鐵酒石酸鹽，經煆燒處理可製備微粒(＜1μm)之鋇鐵氧磁體(M=BaFe12O19)粉末。本研究對1) 酒石酸與陽離子莫耳比例，2) 鋇鐵酒石酸鹽沈澱之生成溶液的pH值，二項變因對BaM相合成之影響作一探討。重要結果分列如下：
1. BaFe12O19相的生成︰
a) 選擇酒石酸/陽離子莫耳比例~1，產出之鋇鐵酒石酸鹽可於250℃分解形成微晶或非晶質鋇化合物與γ-Fe2O3的混合物。此混合物於 700℃反應生成BaFe12O19相，且不需經過BaFe2O4中間相。
b) BaFe12O19相的生成應與γ-→α-Fe2O3相轉換過程有關。其反應生成溫度可低至400℃ (pH=7以及T/C=1.3系統)。生成途徑可由下式表示：
Metal-tartrates γ-Fe2O3＋鋇化合物 BaFe12O19。
2. BaFe2O4相的生成︰
生成機制是藉由BaCO3結晶相分別在450~550℃以及~600℃發生二階段分解後，再分別與γ-以及α-Fe2O3反應合成BaFe2O4，此相可殘留至高溫(T/C=1.3系統)。
3. 單相BaFe12O19微粉的合成︰
選擇酒石酸/陽離子莫耳比例~1，獲得鋇鐵酒石酸鹽並使其於250℃分解形成微晶或非晶質鋇化合物與γ-Fe2O3，則可於700℃，直接合成接近單相且微粒(＜1μm)之BaM粉末。

This study utilized the metal-tartrate method to synthesize submicrometered (＜1μm) barium ferrite (M=BaFe12O19) powders. Two experimental factors that influence the ferrite formation: (1) the molar ratio of tartaric acid/ cation and (2) the pH value of solutions were examined. It is found that:
1. BaFe12O19 formation: The Ba-Fe-tartrates obtained at molar ratio of tartaric acid/ cation (T/C) ~1 would transfer to a mixture of Ba-compound (unidentified amorphous or microcrystalline phases) + g-Fe2O3 at 250oC. The mixture then reacted to form BaFe12O19 at temperature ＞700℃. The BaFe2O4 phase as generally observed during synthesis of the ferrite using solid-state reaction did not occur.
Formation of BaFe12O19 may relevant to g- to a- phase transformation of Fe2O3. The ferrite phase can be formed at temperature as low as 400℃ (selecting pH=7 and T/C=1.3 systems). The formation mechanism for BaFe12O19 formation is:
Metal-tartrates g-Fe2O3 + Ba-compound BaFe12O19.
2. BaFe2O4 formation: The decomposition of barium carbonate (BaCO3, witherite) that occurred at two temperature intervals 450~550oC and ~600oC, respectively can be the controlling factor for BaFe2O4 formation. The Ba2+ cation then reacted with Fe2O3 to form BaFe2O4 that behaved stably, persisting to higher temperatures.
3.The synthesis of mono-phased BaFe12O19 powders then can be obtained using the organo-metallic system of T/C molar ratio ~ 1. Transferring the precipitate to a mixture of Ba-compounds and g-Fe2O3 at 250oC then a direct formation of BaFe12O19 powders can be obtained by calcinations of the mixture at ~700oC.

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