材料分析的演進

對於1980年以前的材料前輩而言，材料分析一詞尚不普遍，那時代對材料顯微結構研究分析的行為稱之為金相分析，因為主要分析的材料為金屬材料。所以，卅年以前的機械系和冶金系的學生大概幾乎都修過金相學。必做的實驗，就是切下一塊金屬材料，通過研磨、拋光等程序後，再加上適當的蝕刻，最後將試片放在光學顯微鏡下觀察，可以看到如圖2的顯微結構。通過金相學分析，研究者可以建立金屬材料強度和晶粒大小的關係，也可以看到材料內是否有析出物、雙晶、疊差、…等結構，推斷這些結構對金屬機械性質的影響。

People might not be familiar with the terminology, MA, before 1980. Before 1980, most of microstructure analyses focused on metal materials. So, work on microstructure analysis was called metallography. Students of department of mechanic engineering and department of metallurgy in colleges all took metallography courses. Everyone cut a small piece of metal, ground and polished it, then put it under a optical microscope after properly etching it. The typical image observed is like that shown in Figure 1. Researchers established relationship of strength and grain size for many metals. Studies of effect of precipitates, twins, and stacking faults …etc. on metals were popular conducted in metallurgy.

圖2. 典型光學金相照片顯示多晶材料的晶粒大小。(感謝環球檢驗科技許傳宗先生提供)

隨著電子顯微鏡的進入材料分析領域，當高能電子進入試片，和試片組成元素的原子交互作用後，產生的訊號除可形成高倍率影像外，部分訊號也提供元素種類，甚至化學鍵結的訊息。顯微結構分析不再只限於影像，微區成份訊息也可也可分析。穿透式電電鏡(TEM)更進一步提供試片的晶體結構訊息。被分析的材料也從金屬擴展到精密陶瓷(fine ceramics)，半導體，等材料，甚至部分有機材料。這時候，金相學一詞逐漸消失，材料分析一詞則逐漸崛起，最後凡是對材料或元件的顯微結構進行分析者統稱材料分析。

When electron microscopes were introduced into the field of MA, besides images of high magnification, information of elements could be extracted, so did chemical bonding state of atoms. TEM can even more take crystallography information out of nano regions. Materials of fine ceramics, semiconductor, and some organics were more and more being analyzed by electron microscopes. The terminology, metallography, was then gradually replacing by materials analysis (MA).

材料分析和病理分析

說到材料分析，對許多人來說可能是很陌生的東西，但是將其連結到病理分析，大家應該會比較有概念。二者確實是很類似的工作，只是材料分析的樣品是來自無生命的個體，而病理分析的樣品是來自有生命，或者曾經有生命的個體。透過高倍率的顯微鏡和者分析儀，探索樣品中的某些特徵物，並找出這些特徵物和事件的關聯性。

People may not know what materials analysis is, but should be familiar with pathological analysis. The principle and process of materials analysis and pathological analysis are quite similar. The difference is that the former deals with samples from matters, while the latter does biological tissue, especially from human bodies. Both of them use microscopes and analyzers to explore samples to find some features which may be connected to the issue under study. 

病理分析的結果通常是提供醫生治療病患者的參考資料，而材料分析的結果則是提供研究者或製程工程師製程改善的方向，以改善材料性質，或產品提高良率。在分析過程中，病理分析師有面對病毒的危險，而材料分析工程師則會面對酸鹼溶劑，甚至有毒物質的危險，二者工作過程和工作性質基本上很相似。

Doctors refer to results of pathological analysis to cure patients, researchers and engineers use results of materials analysis to tune the process to improve the properties of materials or yield. Pathologists have to face the risk of virus in work, MA engineers have to deal with acid-base solvent, some of them are toxic. So, nature of their works are similar too.

材料與材料分析(Materials and Materials Analysis)

凡具有某種特定性質的物質，可以經由特定的製程，單獨或搭配其他物質，形成特性功能的元件者，統稱為材料。這裡的材料通常指的是固態材料。常用的固態材料分為金屬，陶瓷，半導體，有機材料等四大類。

Any matter with some kinds of characteristics, that can be processed alone or with other matters to be a device having some special functions, is called a material. The material we discussed here is limited to solid state materials. Generally, there are four groups of solid state materials: metals, ceramics, semiconductor, and organics (polymers).

材料分析(material analysis, MA)意指運用科學的儀器和科學的方法，解析材料或元件的顯微結構(組成元素，晶體結構，晶粒大小，晶體缺陷…等等)，找出製程、顯微結構、材料性質三者之間的關聯性。 

Material analysis (MA) means to use both scientific methods and scientific instruments to analyze microstructure, including consistent elements, crystal structure, grain size, crystal defects, …etc., of materials or devices, and find the relationship among process, microstructure, and properties.

圖1. 常用的固態無機材料。(from Google websites)