Since he returned to Brazil in early 1991, after completing his post-doctoral studies at NASA (the US Space Agency ) in its Jet Propulsion Laboratory, the physicist Vladimir Jesus Trava Airoldi decided to conduct his research projects with a very well-defined purpose, selecting only those that offered a high scientific level and a high application potential.
Upon his return to work at the National Institute for Space Research (Inpe), in the city of São José dos Campos, in inner-state São Paulo, his first project was to develop synthetic diamonds for applications in space and in industry. “At the time, studies on synthetic diamonds were largely theoretical and there was no way to know just how important they would become,” states Airoldi. What was known was that they provided biological and chemical compatibility, with the lowest attrition coefficient found among solid materials, and that it would therefore be possible to use them as a solid lubricant in satellite solar-panel hinges.
Apart from this, industrial diamonds are a material with higher heat conductivity than all other materials and have a significant optical transmission interval, ranging from infrared light to X-rays, thus allowing applications in cutting and abrasion tools, protectors of surfaces against chemical corrosion, medical-dental tools and others. The initial idea was to develop synthetic diamonds for the space sector, such as heat dissipaters, solid lubricants and optical protectors. However, the researcher thought this was too limited. “Right from the outset the project was launched as a generator of spin-offs, companies that would use the technology,” explained Airoldi.
Two decades later, in December of last year, Airoldi received the 2011 Finep Innovation Award in the Innovative Inventor category for his work. At present, he has 12 patents filed and more than 150 scientific articles have been published by his research group, which comprises 30 people, including researchers, students and those doing post-doctoral studies.
One of the consequences of the initial project was setting up the company Clorovale Diamantes, in 1997, to produce synthetic diamond tips for dental drill-bits. These drill-bits, coupled to ultrasound devices as replacements for the traditional rotation devices, are sold both in Brazil and abroad. “We are the only company in the world to use CVD diamonds in the dental area,” comments Airoldi. CVD (chemical vapor deposition) diamonds are produced with gases such as hydrogen and methane. The patent has already been granted in the world’s main markets, such as the United States, Europe, Australia, Japan and China.
Airoldi says that at first he had to deal with suspicion from the institutes that finance research, which did not want to provide support for projects that have a high application level, and that he was disappointed with businessmen in the medical, dental and metallurgical sectors whom he contacted to present the technology, which needed investment in order to progress. “The 1991 to 1997 period was a somber one, but I stuck with it and then we got approval from FAPESP for the Pipe project. This was Clorovale’s starting point,” he explains. In his opinion, Innovative Research in Small Companies Program (Pipe) project was the chief catalyst for the entire process, especially as this enabled him to set up the company. Since then, four other projects of his were approved by FAPESP in the same modality, plus two thematic projects and three requests for regular research support for his field of research at Inpe.
Choosing dentistry as the first industrial application for the synthetic diamonds was due to a strategy based on the high educational level of dentists and the fact that they need products with added technology to make a difference in their dental surgeries. “Even so, when we began to sell our products in 2003, we faced a lot of difficulties,” says Airoldi. “We sold enough to survive until 2011, when we managed to double our turnover.” Until then, our sales had remained constant at about R$ 700 thousand. The wind only really began to turn in our favor in 2009, when Clorovale began exporting its products after getting approval from the European Union.
In 2010, the company’s business model got an additional boost with support from Criatec, a seed-capital investment fund set up by the National Bank for Economic and Social Development (BNDES) in partnership with Banco do Nordeste do Brasil. Criatec came onboard as a partner and has a 35% stake in the company. At present, Clorovale has nine partners, three of whom are investors, and a total of 23 employees. According to João Furtado, a member of FAPESP’s Coordinating Body for Innovation Research and a professor at USP’s Polytechnic School, Airoldi’s main qualities are tenacity and determination. “He didn’t lose heart even during the most difficult times.”
For Furtado, it is not enough just to have a good idea. “A business involves hard, systematic, planned work.” Additionally, another quality that contributed to the undertaking’s success was that he adopted a different outlook, rather than a merely scientific, technological one. “Over the course of time Airoldi has understood the market and its workings better, and realized that the approach involved several dimensions.”
The researcher says that the advantages of using diamonds in ultrasound devices were not created by his research group. “Dentists had already observed in the 1950s that using drill-bits in ultrasound devices to prepare dental cavities was less painful than the traditional method and didn’t cause bleeding,” he says.
However, this technique did not evolve because at that time there were no diamond tips that could withstand the action of ultrasound when it comes into contact with hard tissue, made up of enamel and dentine. “This was our big idea and my work was to create synthetic diamonds and let them develop onto a metal surface,” he explains. However, that was not enough. It was necessary for it to be extremely adherent. “The diamond’s adhesion to the metal area is the most important part of the invention, the object of the patent.” Behind the secret, there are various developments, such as the density of the gas used, the preparation of the surface in the substructure, along with the temperature, composition and internal pressure of the reactors.
There are now more than 30 models of dental tips that have been developed at the request of dentists and professors. They can be used to remove caries, to file down and do the finishing on teeth, and in the cutting of bone in dental implants. Several university laboratories are teaching students to work with CVD diamond tip technology with ultrasound. “The world’s first ultrasound dentistry course was created at the University of São Paulo in Bauru,” says Airoldi. At present, USP in Bauru has two courses, one in the regular dentistry area and the other in the pediatric dentistry area. The USP School of Dentistry in the São Paulo campus and the Paulista State University (Unesp) Schools of Dentistry in the cities of Araraquara and São José dos Campos also have similar courses.
Synthetic diamonds are not limited just to dental applications. Another of the company’s lines of research, carried out in collaboration with Inpe, concerns amorphous synthetic diamonds, whose carbon structure is not as well organized as that of the crystalline version. Amorphous synthetic diamonds are not as hard as the crystalline ones, but even so are harder than every known metal. The advantage is that, while crystalline diamonds only grow to a few centimeters, and therefore can only be used for small parts, amorphous diamonds can reach several meters. Excellent bactericides, amorphous diamonds can be used for both orthopedic surgeries as well as for coatings in knee prosthetics and heart valves.
More durable and stable
Synthetic amorphous diamonds have also been used in drill-bits tested by Petrobras for drilling oil wells. Traditional drill-bits already use a diamond powder on the tips. In research conducted by Clorovale, small billets (pieces) of synthetic diamond are incorporated into the tip of the drill-bit. In the first test, a small drill-bit, produced with diamond billets up to 20 millimeters long by 2 millimeters, was tested in the drilling of water wells.
The results have been encouraging. The drill-bit turned out to be two and a half times more durable, in addition to cutting 30% faster and giving greater stability to the drill shaft than the conventional, diamond powder-tipped drill-bits. Petrobras decided to test the technology in the drilling of deep oil wells and was satisfied with the result. The company ordered a further two prototype drill-bits from Clorovale and is getting ready to undertake more conclusive trials before the end of the first half of this year.
The amorphous diamonds can also be deposited on large surfaces. Their application enriches the chemical, physical and mechanical properties of materials such steel. The creation of other products apart from dental drill-bits is, in Furtado’s opinion, the third major quality of this undertaking, along with the enterprise’s determination and market-oriented outlook. “The researcher realized that the Pipe program could be a permanent source of support and thanks to this program, it has been possible to broaden the company’s technological horizons with new challenges and new skills.
1. Development of CVD diamond devices for short-term applications (nº 1997/07227-6); Modality Innovative Research in Small Companies Program (Pipe); Coordinator Kiyoe Umeda (Clorovale); Investment R$ 329.585,13 (FAPESP)
2. New materials, studies and innovative applications using CVD diamonds and DLC (diamond-like-carbon) diamonds (nº 2001/11619-4); Modality Thematic Project; Coordinator Vladimir Airoldi (Inpe/Clorovale); Investment R$ 576.456,12 (FAPESP)
3. CVD diamonds for a new high-performance tools concept for perforation and cutting (nº 2006/60821-4); Modality Innovative Research in Small Companies Program (Pipe); Coordinator Leônidas Lopes de Melo (Clorovale); Investment R$ 550.661,41 (FAPESP)
4. DLC films for applications in antibacterial, antifriction, special and industrial applications and in oil well drilling tubes (nº 2006/60822-0); Modality Innovative Research in Small Companies Program (Pipe); Coordinator Alessandra Venâncio Diniz (Clorovale); Investment R$ 505.917,65 (FAPESP)