JPS60230975A - Formation of reinforcing layer on base metal - Google Patents

Abstract

PURPOSE:To improve remarkably the bonding strength of a reinforcing layer to a base metal by recessing the surface of the base metal to be bonded so that the resulting recesses for engagement have the shape of an inverted unfolded fan as the cross-sectional shape and by forming the reinforcing layer while filling the recesses. CONSTITUTION:The piston head 6 of a piston body 5 as the base metal is recessed, for example, so that the resulting recesses 7 for engagement have the shape of an inverted unfolded fan as the cross-sectional shape and are distributed over the whole region of the piston head 6. Ceramics or the like is then thermally sprayed on the whole region of the piston head 6 to form the reinforcing layer 8 filling the recesses 7. The sprayed material flows in the recesses 7 and solidifies, improving the bonding strength of the reinforcing layer 8 to the piston body 5.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a method for forming a reinforcing layer on a base metal for locally reinforcing parts such as aluminum castings with a heat-resistant and abrasion-resistant layer, and particularly relates to a method for forming a reinforcing layer on a base metal such as a ceramic material. The present invention is directed to a method for forming a reinforcing layer of a base metal that can improve the bonding properties of the reinforcing layer and prevent peeling.

[Technical Background of the Invention and Problems Therewith 1 Generally, for automobile parts such as cylinder heads and pistons where heat resistance and wear resistance are locally required, ceramic materials are used in those parts. Research and implementation have already been carried out to form a reinforcing layer made of a solvent or the like for reinforcement.

By the way, this is not a problem if the difference in thermal expansion between the base metal and the reinforcing layer formed on the surface is not very large, but if the difference in thermal expansion is large, such as between metal and ceramic, repeated heating and cooling may be necessary. Due to the thermal shock associated with this, a phenomenon occurred in which the interface between the base metal and the ceramic peeled off. This is due to the fact that the adhesive force is smaller than the stress generated from relative strain with the metal due to thermal changes in the ceramic.

This will be specifically explained based on FIGS. 8 and 9.

FIG. 8 is a plan view showing the piston on which the reinforcing layer is formed, and FIG. 9 is an enlarged view showing section A in FIG. 8.

As shown in FIG. 8, a reinforcing layer 2 of a ceramic material made of, for example, zirconia is formed by thermal spraying on the head portion of a piston 1 made of, for example, an Aβ (aluminum) alloy. The reinforcing layer 2 was peeled off from the interface due to thermal shock such as rapid cooling.

Therefore, as shown in FIGS. 9(a) and 9(b), the adhered surface 3 of the piston 1, which is the base metal, was degreased and then removed.

The surface is roughened in advance by doblasting etc., and before the ceramic material is thermally sprayed, a thin inorganic intermediate adhesive 4 with good adhesion is thermally sprayed on both the base metal and the ceramic material, and then the ceramic material is further applied on top of this. Attempts have also been made to increase adhesion by thermal spraying the material.

In this case, due to the characteristics of the materials, the ceramic material and the adhesive 4 are strongly bonded and integrated, but the adhesive and the piston 1
The adhesive force with the adhered surface 3 is not sufficient, and the reinforcing layer 2 peels off due to thermal shock, and the problem has not yet been fully solved (see FIG. 9(b)).

[Object of the Invention] The present invention focuses on the above-mentioned problems and has been devised to effectively solve the problems.

An object of the present invention is to provide a method for forming a reinforcing layer of a base metal that can improve the bonding properties of a reinforcing layer made of a ceramic material and prevent peeling.

[Summary of the Invention 1 The present invention provides that adhesive force can be improved by forming an engagement recess with an enlarged diameter in the base metal on the adhesion surface of the base metal before forming a reinforcing layer, and in particular, When using spun iron as the base metal, it is easy to burn and gasify! This method was developed based on the fact that the above-mentioned engaging recesses can be easily formed using powder, and the engaging recesses are filled in the adherend surface on which the engaging recesses have been formed, the diameter of which is expanded into the base metal. The gist of this is that the adhesive strength is increased by forming a reinforcing layer.

[Embodiments of the invention] The method of the present invention will be explained in detail below based on the accompanying drawings.

First, a first embodiment will be carried out as shown in FIG. That is, an engagement recess 7 is formed in the attachment surface (piston head) 6 of the piston body 5, which is a base metal, by expanding the diameter into the base metal. The number of the engaging recesses 7 is determined based on the relationship with the adhesive force, and the engaging recesses 7 are arranged evenly over the entire area of the adherend surface 6. To form the engagement recess 7, machining may be performed after the piston body 5 is cast, or a portion corresponding to the engagement recess 7 may be provided in the casting mold, and the engagement recess 7 may be formed at the same time as casting. 7 may be formed.

After forming the engagement recess 7 on the adherend surface 6 in this way,
Next, a ceramic material or the like is thermally sprayed over the entire area of the attachment surface 6 to fill the engagement recess 7 and form a reinforcing layer 8. As a result, the ceramic material flows into the engagement recess 7 whose diameter has been enlarged and hardens, thereby improving the adhesive force between the reinforcing layer 8 and the piston body 5, thereby making the connection between them stronger.

In the above case, the engaging recess 7 has a truncated conical cross section, but is not limited to this, and may have a spherical shape with an open upper end.

Next, a second embodiment will be described based on FIG.

In this case, an engagement recess 9 is formed by drilling a predetermined length of a screw hole in the attachment surface 6 of the piston body 5, which is a VJ-shaped base metal, as shown in the figure. Incidentally, the number and depth of the engaging recesses 9 are determined as appropriate based on the relationship with the adhesive force, as described above.

Once the engagement recesses 9 have been formed in this manner, as described above, next, a ceramic material or the like is thermally sprayed over the entire area of the attachment surface 6 to fill the engagement recesses 9 and form the reinforcing layer 10. . As a result, the ceramic material that has flowed into the screw hole-shaped engagement recess 9 and solidified is firmly bonded to the screw thread, thereby improving the adhesive force between the reinforcing layer 10 and the piston body 5.

In particular, in this embodiment, the attachment surface 6 of the piston body 5
Since the engagement recess 9 can be formed by drilling a screw hole in the screw hole, the machining is greatly facilitated.

Next, a third embodiment will be described based on FIGS. 3 to 7.

In this embodiment, Aβ powder is cleverly used to form the engaging recesses, thereby simplifying the process.

In other words, if A (powder) is mixed with cast iron, the melting point of A (A) is extremely low compared to that of cast iron, so the AI! powder will rapidly burn and gasify, causing cavities that are a cause of defects in cast iron. However, in this embodiment, this is actively utilized to the contrary, and a small amount of Ai! powder is applied to the casting mold corresponding to the surface to be adhered to when casting the piston body to form an engaging recess. First, as shown in Fig. 3, a very small amount of Aβ powder 12 is uniformly applied to the entire portion of a piston-shaped casting mold 11 (a sand mold may also be used) corresponding to the piston head (adhering surface). Coating and forming. At this time, it is possible to easily coat by pre-mixing the beta powder with a liquid agent such as alcohol or water. Metal is poured and the piston body 5 as shown in Fig. 4 is cast and molded.In this case, the applied metal (Al1 powder in this example) is rapidly combusted and gasified by the melting lag of the base metal. Therefore, a base metal and a coating metal that have such thermal characteristics are selected.

By this casting molding, Aβ powder 1 applied to the casting mold 11
2 is rapidly combusted and gasified, and a foam layer 13 is formed on the adhered surface 6 of the piston body 5, as shown in the enlarged view of FIG. Incidentally, FIG. 5 shows an enlarged view of section B in FIG. 4. This foam layer B
The individual holes constitute an engaging quadrant 14 that expands into the base metal. The depth and number of the engaging recesses 14 are determined by the amount of β powder to be applied, and are appropriately selected in relation to the bonding force.

Once the engagement recess 14 is formed in the adherend surface 6 in this way, next, as shown in FIGS. 6 and 7, as described above,
A ceramic material is thermally sprayed over the entire area of the attachment surface 6 to fill the engagement recess 14 and form a reinforcing layer 15 .

FIG. 7 shows an enlarged view of section C in FIG. 6.

As a result, the ceramic material flows into the many engagement recesses 14 and solidifies, thereby improving the adhesive force between the reinforcing layer 15 and the piston body 5, thereby making the connection between them stronger.

In particular, in this third embodiment, in order to form the engagement recess 14, it is sufficient to simply apply /1 powder to the casting mold during casting of the piston body, compared to the first and second embodiments. The work of forming the engagement recess can be greatly simplified.

In this way, according to this embodiment, on the adhesion surface of the base metal,
An engaging recess is formed by expanding the diameter into the base metal, and a reinforcing layer is formed on this adhering surface to fill the four engaging parts, so that the ceramic that flows into the engaging recess and solidifies. The reinforcing layer and the base metal can be strongly bonded to each other, and the adhesive force between the reinforcing layer and the base metal can be strengthened. Therefore, it is possible to exert sufficient adhesive strength to absorb the relative strain force between the metal and the reinforcing layer caused by thermal shock caused by repeated heating and cooling, and to ensure that the reinforcing layer does not peel off. It can be prevented.

In the above embodiments, a case where a reinforcing layer is formed on the piston is described, but the present invention is not limited to this, and a reinforcing layer made of ceramic or the like with excellent heat resistance or wear resistance can be formed on the surface of the casting. All applicable cases are applicable. Furthermore, it goes without saying that the material of the reinforcing layer is not limited to ceramic materials.

[Effects of the Invention] In summary, according to the method of the present invention, an engaging recess whose diameter is expanded into the base metal is formed on the adhering surface of the base metal, and the engaging recess is filled up. By forming a reinforcing layer, it is possible to improve the adhesion between the base metal and the reinforcing layer as much as possible. Therefore, even if relative strain occurs due to thermal shock, the reinforcing layer will not peel off. can be prevented.

[Brief explanation of the drawing]

1 to 7 are explanatory diagrams for explaining the method of the present invention, in particular, FIG. 5 is an enlarged view of section A in FIG. 4, FIG. 7 is an enlarged view of section C in FIG. FIG. 8 is a plan view showing a piston on which a reinforcing layer is formed, and FIGS. 9 to 11 are explanatory diagrams for explaining a conventional method for forming a reinforcing layer. In the figure, 5 is a casting mold, 6 is a bonding property improver, 8 is a piston body as a base metal, 9 is an adhering surface, and 10 is a reinforcing layer. October 17, 1981 Manabu Shiga, Commissioner of the Patent Office 1, Indication of the case Patent application 1986-86696 J2, Title of the invention Method for forming a reinforcing layer of base metal 3, Amendment Patent applicant (017) I1zu Jidochu Co., Ltd. 4, Agent postal code 105 1-6-7-5 Atago, Minato-ku, Tokyo Date of amendment order July 31, 1980 Date (shipment date) 6. Specification to be amended (column for brief description of drawings) and Drawing 7. Contents of amendment (1) Page 10 of the specification, lines 11 to 19 "Figure 1...
...10 is a reinforcement layer. ” [Figures 1 to 7 are explanatory diagrams for explaining the present invention in detail (・Yes, 9, 'I
Fig. 5 is an enlarged view of part B in Fig. 4, Fig. 7 is an enlarged view of part C in Fig. 6, and Fig. 8 is an enlarged view of part C in Fig. 6. 9 is a plan view showing A in FIG. 8.
The enlarged view (5 in the figure) shows the piston body as metal, 6 is the attachment surface, 7.9.14 is the engagement recess, and 8 and 10.15 are the piston body. It is a reinforcement layer. ” to Yaji. [2] Submit the drawings to the appropriate iF' as shown in the attached sheet. ,
(However, please change the contents.) 8. List of attached documents (1) 1 copy of drawings

Claims (1)

[Claims] When forming a reinforcing layer of ceramic material or the like on the base metal, an engaging recess is formed on the adhering surface of the base metal by expanding the diameter of the base metal shoulder, and then the upper i[! (m) A method for forming a reinforcing layer on a base metal, characterized in that the reinforcing layer is formed on a surface to which the base metal is adhered so as to fill the engagement recess.