Answer
Gajiyar gajiya hanya ce ta gazawa da ke faruwa a cikin maɓuɓɓugan ruwan raƙuman ruwa inda madaidaitan yadudduka na waya ke shafa juna yayin lodin keken keke. Wannan ƙananan motsi (fretting) yana cire kariya ta oxide Layer na karfe kuma ya haifar da ƙananan ramuka waɗanda ke aiki a matsayin masu tattara damuwa. Daga ƙarshe, waɗannan ramukan suna fara faɗuwar gajiya waɗanda ke yaduwa ta cikin kaurin waya. Wannan ya zama ruwan dare musamman a aikace-aikacen mitoci masu girma kamar masu keɓewar girgiza. Don hana tashin hankali, injiniyoyi sun ƙayyade busassun man shafawa na fim (kamar MoS2 ko PTFE) ko tabbatar da cewa ruwan bazara ya nutse cikin mai. Binciken gazawa yawanci yana bayyana 'tsatsa' (cocoa) a cikin ƙarfe na carbon ko facin da aka sawa a cikin bakin karfe a wuraren tuntuɓar juna tsakanin jujjuya, tare da facin facin.
