Rafael Borrajo is an associate professor in Mechanical Engineering. His research is focused on materials innovation and characterization, and the use of ion and nanoparticle beams to create/modify materials. Furthermore, he is responsible for the teaching of two courses: Materials Technology and Hydraulics and Machine Systems.
Dr Borrajo completed a MSc (2012) and a PhD (2014) with a focus on material science and space propulsion at the University of California in Irvine, under the supervision of Prof. Gamero-Castaño. He investigated space thrusters (electrosprays) and their interaction with solid surfaces. He studied the energetic impact of electrosprayed nanodroplets on hard crystalline materials, and characterized the resulting surface modifications, e.g. material removal (sputtering), topographic changes and nano-structural transformations (amorphization), to find out the physical mechanisms involved in these phenomena.
As a post-doctoral researcher in the Dpt. of Materials Science and Engineering at KTH in Stockholm, he investigated super-hard composite materials and steels. He participated in the development of cemented carbides and, through materials characterization, provided insight about the effect of the manufacturing process (sintering) and thermal treatment in their resulting nano-structure and properties. In addition, he studied the optimization of steel by controlling phase decomposition and particle precipitation in the nano- and micro-scale. Through his work on materials characterization, he has acquired expertise in the following techniques: scanning electron microscopy (SEM), transmission electron microscopy (TEM), TEM sample preparation with focused ion beams (FIB), electron backscatter diffraction (EBSD), x-ray diffraction (XRD), energy-dispersive x-ray spectroscopy (EDS) and atomic force microscopy (AFM).
As a propulsion engineer at OHB Sweden, Dr. Borrajo worked on systems engineering and developed propulsion systems for spacecraft. He collaborated with Luleå Technical University to find new methods for satellite propellant gauging in-orbit, and with the European Space Agency (ESA) in the design of spacecraft power and propulsion systems with a simpler, lighter and more cost-effective structure.
As a research engineer at the Norwegian company Cardiaccs, Dr Borrajo worked in the development of heart sensors for the monitoring of the cardiac function in real-time to prevent complications during open-heart cardiac surgery.
Formerly at Yale University, Dr. Borrajo conducted pre-doctoral research working with Prof. Fernandez de la Mora. He took part in the development of analytical instrumentation based on ion mobility and mass spectrometry, with the capability to separate and identify traces from gas mixtures in very low concentrations, enabling real-time chemical/medical diagnosis. As examples of his research, he studied the real-time separation of traces in room air for explosive detection, the chemical patterns in human breath and skin vapours for the detection of disease markers (cancer), and biometric identification of people.
Dr. Borrajo completed a BSc (2008) in industrial engineering at the University of Malaga, in Spain. As part of his BSc dissertation, he performed research on fluid/thermal numerical simulations of heat exchangers using computational fluid dynamics (CFD).
Fields of study
Borrajo-Pelaez, Rafael; Hedström, Peter (2018). Recent Developments of Crystallographic Analysis Methods in the Scanning Electron Microscope for Applications in Metallurgy. Critical reviews in solid state and materials sciences . Vol. 43.
Nosko, Oleksii; Borrajo-Pelaez, Rafael; Hedström, Peter; Olofsson, Ulf (2017). Porosity and shape of airborne wear microparticles generated by sliding contact between a low-metallic friction material and a cast iron. Journal of Aerosol Science . Vol. 113.
Ma, Taoran; Borrajo-Pelaez, Rafael; Hedström, Peter; Borgh, Ida; Blomqvist, Andreas; Norgren, Susanne; Odqvist, Joakim (2016). Microstructure evolution during phase separation in Ti-Zr-C. International Journal of Refractory Metals and Hard Materials. Vol. 61.
Borrajo-Pelaez, Rafael; Saiz, Fernan; Gamero-Castaño, Manuel (2015). The Effect of the Molecular Mass on the Sputtering of Si, SiC, Ge, and GaAs by Electrosprayed Nanodroplets at Impact Velocities up to 17 km/s. Aerosol Science and Technology . Vol. 49.
Gamero-Castaño, Manuel; Torrents, Anna; Borrajo-Pelaez, Rafael; Zheng, Jian-Guo (2014). Amorphization of hard crystalline materials by electrosprayed nanodroplet impact. Journal of Applied Physics . Vol. 116.
Borrajo-Pelaez, Rafael; Grustan-Gutierrez, Enric; Gamero-Castaño, Manuel (2013). Sputtering of Si, SiC, InAs, InP, Ge, GaAs, GaSb, and GaN by electrosprayed nanodroplets. Journal of Applied Physics . Vol. 114.
Saiz, Fernan; Borrajo-Pelaez, Rafael; Gamero-Castaño, Manuel (2013). The influence of the projectile’s velocity and diameter on the amorphization of silicon by electrosprayed nanodroplets. Journal of Applied Physics . Vol. 114.
Fernandez de la Mora, Juan; Borrajo-Pelaez, Rafael; Zurita-Gotor, Mauricio (2012). Capillary and Coulombic Effects on the Gas Phase Structure of Electrosprayed Concanavalin A Ions and Its Clusters Cn+z (n = 1−6). Journal of Physical Chemistry B . Vol. 116.
Larriba, Carlos; Hogan Jr., Christopher J.; Attoui, Michel; Borrajo-Pelaez, Rafael; Fernandez Garcia, Juan; Fernandez de la Mora, Juan (2011). The Mobility–Volume Relationship below 3.0 nm Examined by Tandem Mobility–Mass Measurement. Aerosol Science and Technology . Vol. 45.
Borrajo-Pelaez, Rafael; Ortega-Casanova, Joaquin; Cejudo-Lopez, Jose Manuel (2010). A three-dimensional numerical study and comparison between the air side model and the air/water side model of a plain fin-and-tube heat exchanger. Applied Thermal Engineering . Vol. 30.
Borrajo-Pelaez, Rafael; Gamero-Castaño, Manuel (2012). Research on Energetic Impact of Electrosprayed Nanodroplets. 51 p.