可直接淬火之固體粉末滲鉻法

A Powder Chromizing Process with the Advantage of Direct Quenching

卓文彬(W. P. Cho) ； 江國安(K. A. Chian) ； 陳永傳(Y. C. Chen)

《材料科學與工程》 36卷2期 (2004/06) Pp. 111-115

https://doi.org/10.6409/JMSE.200406.0111

摘要

本研究嘗試改良傳統粉末滲鉻法，以旋轉爐取代傳統的滲鉻匣對工件做滲鉻披覆處理，期能改善披覆層的均勻性及簡化後處理的作業程序；並應用CVD的原理來探討各項參數對披覆層厚度及均勻性的影響，以找出工件之最佳滲鉻條件。實驗結果顯示，旋轉爐粉末滲鉻法可於滲鉻後直接淬火，省去二度加熱的能源浪費；其鉻碳化物披覆層厚度均勻、孔洞缺陷少，且滲鉻時間越長、溫度越高，其所生成的鉻碳化物披覆層越厚；再者，當加熱圓筒的容積一定時，所需的氯化銨添加量是一定的，添加更多的氯化銨並無助於提昇鉻碳化物披覆層的厚度；此外，加熱圓筒的轉速必須適當，才可得到最厚的鉻碳化物披覆層；並且由X-Ray繞射實驗得知此鉻碳化物披覆層中的化合物為Cr7C3及Cr23C6，其硬度約為Hv1250~Hv1500。

關鍵字

粉末滲鉻法、旋轉爐、硼砂浴

並列摘要

Due to the disadvantages of the conventional pack chromizing, the present study proposes to use a retort furnace to replace the conventional chromizing pack. It is expected to improve the uniformity of chromium carbide layer and to simplify the post-process after chromizing. Meanwhile, the CVD principle is also employed to discuss the parameters that affect the chromium carbide layer.
The main advantages of chromizing by a retort furnace are that the work piece can be quenched after chromizing without a reheated process, and a comparatively uniform chromium carbide layer with fewer defects can be obtained. The increase in either heating time or temperature can increase the thickness of a chromium carbide layer. Moreover, the rotating speed of heating cylinder must be properly set to increase the thickness of a chromium carbide layer. Besides, a specific amount of NH4Cl powder is needed for a furnace of fixed volume, an excess amount of NH4Cl powder would be unnecessary. Finally, a thin layer consisting of Cr7C3 and Cr23C6 is formed on the surface of the specimen after the chromizing process in the retort furnace, and the hardness of the layer is about Hv1250~Hv1500.

並列關鍵字

Pack chromizing, Retort furnace, Borax bath