October / November 2011 Volume 9 Number 5

Joel Rieken, Andy Heidloff

Good ideas come to Joel Rieken when he’s taking something apart. He was pulling the insides out of his parents’ vacuum cleaner as a kid when he realized he’d like to study “how things work.”  A few years later, as an undergraduate studying materials science, he came up with a way to tackle a tricky materials processing problem while disassembling and cleaning a gas atomizer at the Ames Laboratory.

Fast forward a few more years and Rieken and fellow materials scientist Andy Heidloff have designed a prototype gas atomizer that will make fine spherical titanium powder for use in military, biomedical and aerospace applications. Rieken and Heidloff used several technologies developed at Ames in their design, and have launched a startup company called Iowa Powder Atomization Technologies, or IPAT, to bring the titanium powder to market.“Our system will increase the efficiency of the titanium powder making process,” said Rieken.  “Thus, the cost of the powder will be lower for manufacturers.”

Titanium’s strength, light weight, biocompatibility and resistance to corrosion makes it ideal for use in a variety of parts from small arms and military vehicle components to biomedical implants, aerospace fasteners and chemical plant valves. “While titanium is more expensive than stainless steel, in many cases a titanium part outlasts a stainless steel part and becomes more cost effective in the long run” said Heidloff.

“So, there’s a growing interest in titanium applications. I think we will see it become an important strategic material.” However, titanium’s extreme reactivity with casting mold materials and machining cutting tools makes fabrication of components with a complex final-shape rather expensive. 

Generally, the “buy-to-fly” ratio for titanium aerospace parts is at least 10 to 1, with 90 percent of the original weight being converted to machining chips and scrap.  Traditional part-making techniques like casting, where manufacturers melt and pour liquid metal into molds, can be troublesome when working with titanium because titanium tends to react with the materials used to form molds, requiring extensive machining to convert bulk castings to precise parts.

A possible solution to the casting mold problem is using gas atomization to make a fine, spherical powder form of titanium and using the powder to make parts. In gas atomization of titanium, the metal is melted using a standard commercial process then heated and precisely guided by an Ames-developed pour tube into a high intensity atomization nozzle, also developed at Ames Lab. The metal is then sprayed out in a fine droplet mist. Each droplet quickly cools and solidifies, creating a collection of many tiny spheres, forming fine titanium powder. Manufacturers can then pour the powder into precise molds and press it together at high temperature to form parts.

“In addition to getting around the difficulties with using molten titanium, using titanium powder has the benefits of conserving processing time and energy, and it produces less waste material,” said Rieken. “The overall process is better, except for the current problems of higher cost and lower availability of titanium powder. But those are the two problems IPAT is seeking to solve.”

Solving problems is what sparked Rieken and Heidloff’s interest in studying materials science when they started college at Iowa State University.

“I was always interested in tinkering with things to see how I could improve them,” said Rieken. “And I’m drawn to working with metals, especially hot metals.” So Rieken’s undergraduate research assistant job working in a gas atomization lab at Ames Laboratory was a good fit. Meanwhile, Heidloff was researching other areas of materials processing.The two were completing homework together one evening when Rieken told Heidloff about his idea for a titanium gas atomizer. Heidloff had experience in computer drafting, so he converted Rieken’s design sketches to CAD drawings. 

The two then worked together to develop the design of the titanium gas atomizer.  Rieken and Heidloff put proposals together to fund building a prototype gas atomizer, secured awards, wrote a business plan, and, eventually, built the atomizer—all in their free time away from their undergraduate and, later, doctoral graduate class work and research.

Heidloff recently finished his Ph.D. at Iowa State and is a postdoctoral researcher at Ames, while Rieken expects to finish his doctorate in the coming months.

Next up is refining the design and building an even larger version of the gas atomizer.  For this, Rieken and Heidloff are working with the Quad Cities Manufacturing Lab at the Rock Island Arsenal in Rock Island, Ill. The QCML is a non-profit center dedicated to research, development and training in titanium and other lightweight, advanced materials. Rieken and Heidloff hope that the Army will be one of their first customers, using IPAT’s titanium powder in military applications.

“But we see the potential for titanium powder to be used by manufacturers in a variety of areas, from making jewelry all the way to building aircraft,” said Rieken. “And, as native Iowans, we’d like that titanium powder to come from an Iowa company, using scientific developments made in Iowa at the Ames Laboratory.”

Rieken and Heidloff credit collaboration with their success so far. “We found out that while we are good problem solvers on our own, together our methods are much better,” said Heidloff.  “Plus, scientific research and launching a startup company are not your typical eight-to-five jobs, so it’s best if you go into a project trusting the other person is hardworking and easy to get along with.” 

“We also owe a lot to our collaboration with Ames scientist Iver Anderson, who has more than 20 years of experience in atomization,” said Rieken. “Our gas atomizer is possible thanks to the early experience I had working in atomization at Ames and the materials processing discoveries made at the Ames Lab,” said Rieken.

Breehan Gerleman Lucchesi is a writer at Ames Laboratory Public Affairs.