PIRE: High Temperature Ceramic Fibers: Polymer-Based Manufacturing, Nanostructure, and Performance

Gurpreet Singh（堪萨斯州立大学）、Himanshu Jain（利哈伊大学）、Peter Kroll（德克萨斯大学阿灵顿分校）、Alexandra Navrotsky（加州大学-戴维斯分校）、Rishi Raj（科罗拉多大学博尔德分校）燃气轮机用单晶高温合金叶片可能是上个世纪能源和运输部门最重大的发展。它增强了我们的军事实力，使民用飞机能够绕地球飞行一半。然而，用金属材料制成的燃气轮机的操作温度的进一步提高受到其熔点的限制。因此，下一阶段必须基于高温陶瓷。这些用于燃气涡轮机发动机的高科技材料是渗透有陶瓷基质的陶瓷纤维的复合材料，两者都由非氧化物陶瓷（例如碳化硅）制成。纤维是这种陶瓷基复合材料（CMC）技术的基础，通常通过有机硅聚合物的热分解得到。CMC有望在燃气轮机的工作温度上实现量子飞跃，这可能会在未来几年内将发动机推力提高25%，同时将燃料消耗降低10%。不幸的是，美国在非氧化物纤维制造的加工和创新科学技术方面远远落后于日本和欧洲。为了使美国具有竞争力，该PIRE计划将扩大基础科学和技术的研究，并培养具有纤维加工和性能专业知识的专业人员。该计划将利用美国研究人员与海外同行建立的关系。具体而言，美国PIRE团队成员将带来聚合物衍生陶瓷（PDC）的结构和热化学机械性能表征方面的专业知识，而国际合作伙伴将提供陶瓷前聚合物和非氧化物陶瓷纤维方面的专业知识。他们将共同培养材料科学和工程这一关键领域的下一代学生。来自美国的7至10名博士和20名本科研究学者将通过双学位课程接受陶瓷纤维研究方面的培训，并交流访问日本和欧洲（英国，法国，德国，意大利）的PIRE成员机构。根据该计划建立的社区将包括年轻的研究人员，其中至少50%是女性，代表性不足和第一代上大学的学生。它们将成为未来陶瓷纤维持续创新和科学研究的支柱。研究团队预计，在未来十年内，该纤维计划将发展成为一个成熟的CMC计划，其中基体和纤维都是由美国的聚合物制造的。该PIRE项目的研究部分将专注于开发下一代多组分PDC纤维，该纤维在Si/C/N/O系统中通过系统地了解结构-性能-加工相关性，从而导致优良的上级性能。该项目的关键方面是：（a）设计适合于拉丝的新型陶瓷前聚合物，（B）陶瓷前聚合物的热处理，以获得具有所需形态、化学稳定性和微观结构的多组分陶瓷纤维，（c）蠕变和热化学性能的测量，以及（d）陶瓷纤维氧化行为的建模。将进行从头计算，将实验测量（例如高温量热法）与陶瓷纤维的纳米结构关联起来。此外，还将评估经济评估和PDC纤维制造对资源的影响，以确定新的科学技术在最早阶段的影响和可行性。该项目的成功完成将导致：（i）创建新的美国CMC科学和技术，（ii）一批本科生和研究生将在美国学术界，工业界和国家实验室实施这一专业知识，以及（iii）一个充满活力的国际社会，通过其多样性将大大加快这一关键领域的进展。

Gurpreet Singh (Kansas State University), Himanshu Jain (Lehigh University), Peter Kroll (University of Texas at Arlington), Alexandra Navrotsky (University of California - Davis), Rishi Raj (University of Colorado Boulder)The single crystal superalloy blade for gas turbines may have been the most significant development in energy and transportation sectors in the last century. It empowered our military prowess, and enabled civilian aircraft to fly half way around the world. Further advancement in the operating temperature of gas turbines made with metallic materials, however, is limited by their melting points. So the next phase must be based upon high-temperature ceramics. These high-tech materials for gas turbine engines are composites of ceramic fibers infiltrated with a ceramic matrix, both made of non-oxide ceramics such as silicon carbide. The fibers, which are the foundation of this ceramic matrix composite (CMC) technology, are generally derived through thermal decomposition of organosilicon polymers. The CMCs hold the promise of quantum leaps in the operating temperature of gas turbines, which may increase engine thrust by 25% while decreasing fuel consumption by 10% just within the next few years. Unfortunately, the United States is far behind Japan and Europe that lead the science and technology of processing and innovation in non-oxide fiber fabrication. To make the US competitive this PIRE program will expand research in the basic science and technology and train professionals with expertise in fiber processing and properties. The program will leverage the relationships that researchers in the US have established with their counterparts overseas. Specifically, the US PIRE team members will bring expertise in structure and thermo-chemo-mechanical property characterization of polymer-derived ceramics (PDC), whereas international partners will offer expertise in pre-ceramic polymers and non-oxide ceramic fibers. Together they will train the next generation of students in this crucial area of materials science and engineering. Seven to ten doctoral and twenty undergraduate research scholars from the US will receive training on ceramic fiber research via dual degree programs and exchange visits to PIRE member institutions in Japan and Europe (UK, France, Germany, Italy). The community built under this program will include young researchers comprising of at least 50% female, underrepresented and first-generation-to-attend-college students. They will serve as the backbone for continued innovation and scientific research on ceramic fibers far into the future. The research team foresees that the fiber program will evolve into a full-fledged CMC program, where the matrix and the fibers are manufactured from polymers in the United States, within a decade.The research component of this PIRE project will focus on developing the next generation multi-component PDC fibers of carefully selected compositions within the Si/C/N/O systems through systematic understanding of structure-property-processing correlations, leading to superior properties. Key aspects of the project are: (a) design of new pre-ceramic polymers suitable for drawing fibers, (b) thermolysis of pre-ceramic polymers to obtain multi-component ceramic fibers with desired morphology, chemical stability and microstructure, (c) measurements of creep and thermochemical properties, and (d) modeling of the oxidation behavior of ceramic fibers. Ab-initio calculations will be performed to correlate experimental measurements, such as from high temperature calorimetry, to the nanostructure of ceramic fibers. Further, economic evaluation and the impact of PDC fiber manufacture on resources will be assessed to determine the implications and viability of new, science-based technologies at the earliest stages. Successful completion of the project will thus lead to: (i) the creation of new US-based CMC science and technology, (ii) a cadre of undergraduate and graduate students who will implement this know-how in US academia, industry and national laboratories, and (iii) a vibrant international community that through its diversity will greatly accelerate progress in this critical field.