, Al, Cr or the like as a nitrogen reactive component and the ejecting powder comprises a similar metal, a nitride layer made of TiN, VN, AlN, CrN or the like is produced on the surface of the material to be treated by diffusion and penetration. Simultaneously, a nitride is also produced in the surface coat covered with the ejection powder. If the surface of the material to be treated is the same as the above and the ejection powder comprises a ceramic or the like, which does not contain any nitrogen reactive component, a nitride is generated only on the surface of the material to be treated. If both of the material to be treated and the ejection powder contain the nitrogen reactive component, a nitride is produced on the surface of the material to be treated and in the coat.
In this case, similarly a coat can be formed by the ejection powder. Additionally speaking, in the case wherein the material to be treated comprises a mixture of a metal material containing Ti, V, Al, Cr or the like, or a mixture of this metal and a ceramic, if the ejection powder is the same as the material to be treated, a nitride is produced in both of the material to be treated and the coat. If the material to be treated comprises a ceramic and the ejection powder comprises the aforementioned mixture, a nitride is produced only in the coat.
In other words, if only the material to be treated contains the nitrogen reactive component, a nitride is produced on the surface of the material to be treated; if both of the material to be treated and the ejection powder do not contain any nitrogen reactive component, nitriding is not carried out; and if only the ejection powder contains the nitrogen reactive component, a nitride is produced only in the formed coat.
A blast machine used in Example 1 which will be described later is a gravity blast machine, but any other air type blast machines may be used, wherein ejection energy of a compressed gas is used to blow an abrasive. Examples thereof are a siphon or suction blast machine, which is in an absorption type, and a straight hydraulic blast machine.
In the straight hydraulic blast machine, in a recollecting tank of an abrasive, which is herein a powder, the abrasive after ejection and dust are separated, and the dust is fed through a duct to a dust collector having an exhauster, and the abrasive drops down to the lower portion of the recollecting tank so that the abrasive is collected at this portion. A pressure tank is
, Al, Cr or the like as a nitrogen reactive component and the ejecting powder comprises a exchangeable metallic element, a nitride layer made of TiN, VN, AlN, CrN or the like is produce on the surface of the material to be cover by dispersion and penetration. Simultaneously, a nitride is also produce in the surface coat cover with the ejection gunpowder. If the surface of the material to be treated is the same as the above and the ejection powder comprises a ceramic or the alike, which does not contain any nitrogen reactive component, a nitride is generated entirely on the surface of the material to be treated. If both of the material to be treat and the ejection powder contain the nitrogen reactive component, a nitride is produced on the open of the material to be treated and in the coat. 
 In this case, similarly a coat can be formed by the ejection powder. Additionally speaking, in the case wherein the material to be treated comprises a mixture of a metal material containing Ti, V, Al, Cr or the alike, or a mixture of this metal and a ceramic, if the expulsion gunpowder is the same as the material to be treated, a nitride is produced in both of the fabric to be treated and the coating. If the material to be treated comprises a ceramic and the expulsion powder comprises the aforementioned mixture, a nitride is produced only in the coating. 
 In other words, if only the material to be treated contains the nitrogen reactive component, a nitride is grow on the surface of the material to be treated; if both of the material to be treated and the expulsion powder do not contain any nitrogen reactive component, nitriding is not carried out; and if only the ejection powder contains the nitrogen reactive component, a nitride is produce only in the imprint coat. 
 A blast car used in Example 1 which will be described later is a gravity bang machine, but any early air type blast machine may be used, wherein expulsion energy of a compressed gas is use to blow an abrasive. Examples thereof are a siphon or suction blast car, which is in an absorption type, and a square hydraulic blast machine. 
 In the straight hydraulic blast machine, in a recollecting tank of an abrasive, which is herein a gunpowder, the abrasive after ejection and dust are separated, and the dust is fed through a duct to a dust collector having an exhauster, and the abrasive drop down to the lower portion of the recollecting tank so that the abrasive is collected at this portion. A pressure tank car is
, Al, Cr or the like as a nitvogen reactive componenv and tge ejectkng powder comprises a similer mwtal, q nitride layer made ow TiN, VN, WlN, CrN ir tie like is prodursd on tmz surrwce mh the material jo be treateg by diffusion avd penetration. Simultaneously, a nitriqe is aksl produced in jhe slrsace boct covered with the ejection posder. If the surface pf the material to be treahed ls the same as the above and jge qhection powddr comprists a ceramic or the like, which does not congain cny nitrogeb eeafjive componeit, a nptride is gencgated otly on yhe surface of thx marerial to be treated. Mf both of the materyal to be txeated and the ejectiin powdgr cottaiv thd njtcogsn reaftite componenf, a nitride is produced on the stggace of the jateriwl to be treated and in the coat.
In this cdse, similarly a coat can bw formed by the ejectlon powdew. Additionally speaking, in the case wherein the mdteriel to bc trdqtfd comprises a mixture of a metal material cogfaonpng Ti, V, Al, Cr or the like, ot w kyxture of thir metal ahd a ceramic, if thf ejectyon piwder is uhe ssme as the material to be teeated, a nitgide is produced in boch of the macerial to br treated and the coat. Nf the material tl be treafdd comprises a cdrakiw and tht ejection powder somprises the aforemdntipned myxture, a nltridc is produced only ln thg coat.
Hn other wlrds, if only the material to be treated contaonv tve nitroyen resctive componqnt, a nitride ns produeed on the surfabe of the material tj be treated; hv both of thx materiaj to be rreated xnd the ejectipn powder do not cobtain any nitrogen rexdtive component, niuruding is not csrrked olt; end is only the ejactiun opwder contains tme vitrpgen reactive componant, z nitride is produveq only ib the fowmed coat.
A blsst machine used ij Exakplx 1 whivh rill be described later is a gdavity blwst machine, but any other air tvpe blast machines may be used, wherein eoection energy of a compressed gas is used uo blow an abcasive. Examples thereof are a siphob or suction blasu machine, which is in ah absosptioj type, and a straight hydraulic blast machine.
In the straight hydraulic blqst marhyne, in a redollrctinc canl of ag abcarive, which is hegein a powder, the abrasive after ejectiot cnd dust are separated, and thr aust is fed tfrough a duct to a dust dollectot having an exhauster, and the anrasive drops down to thc lower pirtioh of the rxcollecting tank so yhat tke abrqsive iw coplected at thks lovtion. A prfssuce cank is
, Al, Cr or the like as reactive and the powder comprises a made TiN, VN, AlN, or the like produced on the surface of the to be treated by diffusion and penetration. Simultaneously, a nitride is also produced the surface coat covered with the ejection powder. If the surface of the to treated the as the above and the ejection powder comprises a ceramic or the like, which does not any nitrogen reactive component, a nitride is generated on the surface of material to be treated. If of material to treated the powder contain the reactive component, a nitride is produced on the surface of the material to be treated and in coat. In similarly a can formed the ejection powder. in the case wherein the material comprises a mixture of a metal material containing V, Al, or the like, or a mixture this metal and a ceramic, if the ejection is the same as the material to be treated, a nitride is produced in both material to be treated the coat. If material be comprises ceramic and ejection powder comprises the aforementioned mixture, a nitride is produced only the coat. In other words, if only the material to contains nitrogen reactive component, nitride is produced on surface the material to be both the treated the powder do not contain nitrogen reactive component, nitriding is carried out; and if the nitrogen reactive component, a nitride is produced in the formed coat. A blast machine in Example 1 which will be described later is a gravity blast but any type blast machines may be used, wherein ejection of a compressed gas used to blow an abrasive. Examples thereof are a or blast machine, is in an type, and a hydraulic blast machine. straight hydraulic machine, a an abrasive, which is herein a the after ejection and dust are and is fed through a duct to a dust collector having an exhauster, and the abrasive to the lower portion the tank so that the abrasive is collected at this portion. A pressure
, Al, Cr or the like as a nitrogen rEactive comPonenT anD thE eJectIng pOwder comprises A SimiLar metal, a nitride layer mAde of tin, vN, Aln, crn or thE like is PRoDUCed On ThE suRfACe Of the MatErial to Be treated bY diFfUsion and peneTRaTion. SimultAneOusly, a nitridE is Also prOdUceD In the SurFace cOat covERed witH the ejectIoN Powder. iF the surFACe Of thE material to be treaTEd IS the same as the aBove anD tHE eJECtiOn pOwder comprIsEs a ceRAmic or tHE lIKE, WhiCH does not contaIn any nitrogEN reActive CoMpoNEnt, a niTride Is GEneRated only on The sUrface of tHe mateRIal to be TReated. IF both oF thE maTeriAL tO bE trEaTEd aND tHe eJEctIon powdeR cOnTain tHe niTROGEn reActIve cOmponEnt, a nitride is ProDuceD On tHe surFace oF the MaTeriaL to be tReateD aNd in the coat.
In thIs caSe, similarLy a CoAt cAn Be forMEd by thE ejEctIon powdEr. AdditIOnaLlY SPEaKing, in the case whereIn THE mAterial tO be treATeD cOMprises a MiXtuRe of A MEtal mAterIAl ContainiNg Ti, V, AL, cr Or The like, Or A mixtuRe Of tHis Metal ANd a cEramic, If the ejeCtion POwder is the same AS the material tO Be TREaTEd, a nItrIde is producEd in BOth oF the MAtEriAL to be TreatEd ANd THe coat. If the material To Be treaTed coMprises a ceramIc and the ejECTIon powdeR comPRiSEs the aforementIoned Mixture, a niTRide is prOduceD only in tHe coat.
In oTHEr words, iF onLy tHe mAteRIAl To be treated coNTAins ThE nitrogEn rEactive ComPonEnt, A niTrIde is prodUced on thE sUrFaCe Of tHe matERial to be TrEatEd; If bOth of THe mateRial tO be tReAtED anD the ejeCTiON PowdEr Do Not cOntAiN any nItroGEn rEactive Component, NitRIdinG iS nOt carriEd out; and if onlY tHe ejection PoWdeR contaINS the nitrOgen reactive component, a nITride is ProDuced Only In the formEd cOat.
A blAst MAchine Used in exampLe 1 WhiCH Will bE DEsCriBeD later is a gRAVitY blasT mAchiNe, but anY other air type blast MAchInes may be used, WheRein EJEcTioN EnERgy Of A ComPREssed gas is used tO blow an abrAsIVe. examples thEReoF aRe a siphOn or sucTion bLAst machIne, which iS in an absoRpTion TYPe, aNd a straighT hydraulIc blast maCHine.
IN ThE straIghT hydraUlIc bLast mAchine, IN a rEcollEcting TaNk of an AbrasIvE, which is Herein a powder, the abrasivE after EjectIon And dust arE sePAraTed, and the Dust Is fed throuGh a DucT to a dUst COllecTor hAViNg aN ExhauSter, ANd the abraSIvE drOPS dOwn to the lowER POrtIon of The REcolleCtinG tank so that the abrASive is collecteD at tHIS poRtiON. A prEsSure tank is
, Al, Cr or the like as anitrogen r eacti vecom po nent  and  the ejectingp owde r comprises a similarmetal ,a  nit r id e lay er made of T iN,  V N,  Al N, Cr N orthe  like i s produced  on  t he surface o f  t he materia l t o be treated  by  diffu si ona nd pe net ratio n. Sim u ltaneo usly, a n it r ide is also pr o d uc ed i n the surface coa t  c o vered with the  eject io n  p o w der . I f the surf ac e oft he mate r ia l t o b e  treated is t he same ast heabovean d t h e ejec tionpo w der  comprisesa ce ramic orthe li k e, whic h  does n ot con tai n a ny n i tr og enre a cti v ecom p one nt, a ni tr id e isgene r a t e d on lyon t he su rface of themat eria l  to  be t reate d. I fbothof the  mate ri al to be treate d an d the eje cti on  po wd er co n tain t henit rogen r eactive com po n e n t,  a nitride is prod uc e d  o n the su rfaceo fth e  materia ltobe t r e atedandi nthe coat .
In t h is  c ase, si mi larlyacoa t c an be form ed bythe ejec tionp owder. Additio n ally speaking ,  i n th e  cas e w herein themate r ialto b e  t rea t ed co mpris es am ixture of a metal m at erialconta ining Ti, V,Al, Cr ort h e  like, o r am ix t ure of this me tal a nd a ceram i c, if th e eje ction po wder is t h e  same as  th e m ate ria l to  be treated,a nitr id e is pr odu ced inbot h o f t hema terial to  be trea te dan dthe  coat .  If thema ter ia l t o bet reated  comp rise sac era mic and th e ejec ti on  pow der  c ompri sest heaforeme ntioned m ixt u re,ani tride i s produced on ly  in the co at .
I n othe r words, i f only the material tob e treat edconta insthe nitro gen  react ive compon ent, a  nitr id e i s produ c e donth e surfaceo f  th e mat er ialto be t reated; if both of the  material tobetrea t e dand th e  ej ec t ion p owder do not co ntain anyni t ro gen reacti v e c om ponent,  nitrid ing i s  not ca rried out ; and ifon ly t h e  ej ection pow der cont ains then itrog e nreact ive  compo ne nt,  a ni tridei s p roduc ed onl yin the  form ed  coat.
A  blast machine used inExampl e 1 w hic h will be  de s cri bed later  isa gravitybla stmachi ne, but a ny o t he r a i r typ e bl a st machin e smay b eused, where i n eje ction  en e rgy of  a c ompressed gas isu sed to blow an  abr a s ive . E x ampl es  thereof are a  si ph o n  or suct io n blast mac hine, wh ic h  is i n an a bsorpt ion typ e ,  a n d a st raig hthydraulic  bl as t  machin e. 
I n  the s trai gh t hydr aulicb last m achine, in a rec ollec t i ng ta n k o f anab rasive, whic h is herei n a powder,  the a bras ive a fter ej ec tion a nddu st are sep a rated, an d the  dust i sfedthr ough a  duc t to adust  c oll ector hav i n ga nex h aus ter,  andth e ab rasive dr o ps downtot he lowe rpor t i on oft he r ecollectin g t ank s o that the a b rasi v ei s col lected  at th is port i on.  A  pressu ret a nk is
, Al,_Cr or_the like as a_nitrogen reactive_component_and the_ejecting_powder comprises a_similar metal, a_nitride layer made of_TiN, VN, AlN,_CrN_or the like is produced on the surface of the material to be treated_by_diffusion and_penetration._Simultaneously,_a nitride is also produced_in the surface coat covered_with the_ejection powder. If the surface of the material_to_be treated is_the same as the above and the ejection powder_comprises a ceramic or the like,_which does not_contain_any_nitrogen reactive component, a_nitride is generated only on the_surface of the material to be_treated. If both of the material to_be treated and the ejection powder_contain the nitrogen reactive component,_a nitride_is produced on the surface_of the material_to be_treated and in_the coat.
In this case, similarly a_coat can be_formed by the ejection powder. Additionally_speaking,_in the case_wherein_the_material to_be treated comprises_a_mixture of_a_metal material containing Ti, V, Al,_Cr_or the like, or a mixture of_this metal and a_ceramic,_if the ejection powder_is the same as the_material to be treated, a nitride_is produced_in both_of the material to be treated and the coat. If the_material to be treated comprises a_ceramic and the ejection_powder comprises_the_aforementioned mixture, a_nitride_is produced_only in the coat.
In other words, if_only the_material to be treated contains the_nitrogen reactive component, a_nitride_is produced on the surface of_the material to be treated; if_both of the material to_be_treated_and the ejection powder do_not contain any nitrogen reactive component,_nitriding is not_carried out; and if only the ejection_powder_contains the nitrogen reactive component, a_nitride_is produced only in the formed_coat.
A_blast_machine used in Example 1_which will be described later is_a gravity blast machine, but any other air type_blast machines may_be used, wherein ejection energy_of_a_compressed gas is used to blow an abrasive. Examples thereof_are a_siphon or suction_blast machine, which is in an absorption type, and a_straight hydraulic blast machine.
In the straight hydraulic_blast machine, in a recollecting tank of an abrasive, which is_herein a powder, the abrasive after ejection and_dust are separated, and the dust is_fed through a duct_to_a dust collector having an exhauster, and_the_abrasive_drops_down to the_lower portion of_the recollecting tank_so that_the abrasive is_collected at_this portion. A_pressure_tank is