| 摘要: | 材料科學的傳統研究一直以結晶材料爲主，工業上所應用的金屬材料也大部分是結晶材料。相反的，非晶材料(Amorphous Materials)是最近十年來才注意的後起之秀。至於所謂奈米結構材料(Nano-stuctured Materials)更是最近十年來，才受發掘的材料新領域。本文所探討的新材料，非晶與奈米材料(Amorphous and Nano-crystalline Materials)或簡稱ANC結合材，正是這三種新舊材料都共存一體的新世紀材料。
這三合一新材料可爲材料科學上的一大突破，它涵蓋三種材料結構的優點並抵消一些本質上的缺點，而將材料強化的機制充分又巧妙發揮的近乎理想的材料。將材料的機械性質（如高度、硬度、韌度及抗磨耗等）、電磁性質（如高飽和磁束密度，低抗磁力，高導磁力及高電阻等）以及化學性質（抗腐蝕等）都集於一身或一綱打盡的創新力和想像力不是純粹的技術問題，更不是一般複合材料上的成分合成的方法而已忱種觀念或思想上的突破或新方向的此志正是本文所特別重視而竭力追求並推崇的。
本文指出非晶與奈米晶材料的歷史追溯應該回到將近三十年前Turnbull和Chen（陳鶴壽博士）等先驅者發現非晶塊材(Bulk Amorphous)的新製程及理論根據的關鍵性。另一個重要轉類點是七、八年前Prof. Inoue（井上）及他在日本東北大學的研究群所發展成功的1~10K/s超低冷卻速度的非晶塊材及以熱理生長奈米級晶粒上述的非晶塊材。這兩件歷史性關鍵點與轉類點的精神，目前繼續推動世界先進各國從事這項ANC新材料的探索與應用。
形成非晶塊材與奈米晶粒的共存材料的理論與械制雖然尚未完全命成熟，本文目前較偏榭於井上教授所主張的『三大經驗原則』，也則：(1)至少需要三處金屬成分的參與，(2)金屬間的原子半徑差異在12%以上，(3)金屬間的混合熱△H(下標 max)爲很大的負值。工業上的應用近年來已經陸續出現，其範圍也相當廣泛，涵蓋：(1)運動器材，(2)醫工材料，(3)光電材料，(4)連接器材料，(5)能源材料，及(6)磁性材料等。本文列舉三四項可行例子說明應用上的優越條件。
有鑑於國內在這方面研究方興未艾，亟需以跨校、跨產業界的方式，在政府輔助下加速研究與應用，乃呼籲能夠成立『非晶與奈米材料研發中心』，延聘國外幾位專家指導，促使台灣早日在非晶材料方面能夠擠入世界研究之林。
Traditionally the crystalline materials have been the main focus of materials science, and likewise of most industrial applications. In comparison, amorphous materials are new players in the field, having arrived no longer than 30 years ago. As for the nano-crystalline materials, they are an even newer entity of the recent 10 years. This paper is a brief review of a composite of three old and new materials, named, ”amorphous and nano-crystalline materials” or abbreviated as ANC new century materials.
Undoubtedly such a new composite material is a great breakthrough in the history of materials science. It reserves most of the advantages of those three materials, wisely avoids those intrinsic weaknesses, and tactically utilizes several strengthening mechanisms to the point of near perfection. It encompasses mechanical strength (e.g., high strength, hardness, toughness, wear resistance, etc.), soft magnetic advantages (e.g., high saturation density, low coercivity, high permeability, and high resistivity, etc.), and chemical stability or corrosion resistance. It is not just a pure technical capability, nor a simple materials composite of various elements, when it is actually driven by an innovative and imaginative force, plus a consorted effort of pulling together three distinct materials characteristics. In this paper we are very much concerned for and eagerly in pursuit of such a conceptual and deliberate guidance behind technological advance.
In this paper we are also interested in the historical significance. First, the pioneering work by Turnbull and Chen (Dr. H. S. Chen) in early 1970 marked the beginning key point for new process and theoretical significance in the discovery of bulk amorphous. Second, another significant turning point came to our attention about 7~8 years ago, when Prof. Inoue and his research group at Tohoku University in Japan succeeded in making bulk amorphous rods at a slow cooling rate of 1~10 K/sec. Furthermore in a subsequent annealing or controlled cooling they were able to form a nano-crystalline structure within an amorphous matrix.
The spirit which inspired these historical landmarks is still working behind the scene to drive those who are pursuing ANC new materials for further understanding and applications.
Since the theories and mechanisms behind the formation/making of amorphous nano-crystalline materials are still not fully understood, the ”Three Experienced Principles” proposed by Inoue are still the best phenomenological description of such materials. They state that: (1) At least three different metallic elements are required, (2) Atomic radii should differ by or more than 12%, (3) Enthulpy of mixing, H(subscript mix), should be a large negative value.
Industrial applications are quite demanding. They encompass a wide range of applications, namely, (1) sports equipment, (2) medical engineering materials, (3) optoelectronic materials, (4) connector materials, (5) fuel-cell electrode materials, (6) soft and hard magnetic materials, etc. In this paper we could only pick a few of them and explain them to some detaill.
Toward the end of this paper, we earnestly suggest that along with the effort in research and development of the ANC materials, a Center for Research and Development of Amorphous and Nano-Materials should be established in Taiwan with aid from government. The Center is to attract some well known world experts or scholars to lead some R & D projects, to train a group of younger scientists and engineers, and to propel us into international circles of amorphous and nano-crystalline research. |
