▁fabric ate ▁metal ▁matrix ▁compos ites . ▁ ▁Sur face ▁material ▁may ▁be ▁las er ▁cl added ▁directly ▁onto ▁a ▁highly ▁str essed ▁component , ▁i . e . ▁to ▁make ▁a ▁self - lub ric ating ▁surface . ▁However , ▁such ▁a ▁modification ▁requires ▁further ▁industrial ization ▁of ▁the ▁cl adding ▁process ▁to ▁adapt ▁it ▁for ▁efficient ▁mass ▁production . ▁Further ▁research ▁on ▁the ▁detailed ▁effects ▁from ▁surface ▁top ography , ▁material ▁composition ▁of ▁the ▁las er ▁cl added ▁material ▁and ▁the ▁composition ▁of ▁the ▁add itive ▁package ▁in ▁the ▁lub ric ants ▁on ▁the ▁trib ological ▁properties ▁and ▁performance ▁are ▁prefer ably ▁studied ▁with ▁trib ometric ▁testing . ▁ ▁Process ▁The ▁pow der ▁used ▁in ▁las er ▁cl adding ▁is ▁normally ▁of ▁a ▁met all ic ▁nature , ▁and ▁is ▁inject ed ▁into ▁the ▁system ▁by ▁either ▁co ax ial ▁or ▁later al ▁no zz les . ▁ ▁The ▁interaction ▁of ▁the ▁met all ic ▁pow der ▁stream ▁and ▁the ▁las er ▁causes ▁mel ting ▁to ▁occur , ▁and ▁is ▁known ▁as ▁the ▁m elt ▁pool . ▁ ▁This ▁is ▁depos ited ▁onto ▁a ▁substr ate ; ▁moving ▁the ▁substr ate ▁allows ▁the ▁m elt ▁pool ▁to ▁solid ify ▁and ▁thus ▁produces ▁a ▁track ▁of ▁solid ▁metal . ▁ ▁This ▁is ▁the ▁most ▁common ▁technique , ▁however ▁some ▁processes ▁involve ▁moving ▁the ▁las er / no zz le ▁assembly ▁over ▁a ▁station ary ▁substr ate ▁to ▁produce ▁solid ified ▁tracks . ▁ ▁The ▁motion ▁of ▁the ▁substr ate ▁is ▁gu ided