Ever since the arrival of Windows95 from Microsoft Corporation in 1995, the spread of PCs in the home has increased dramatically. Although they have become less prominent in recent years due to the expansion and spread of smartphones and tablet devices, they are still an essential terminal when handling large amounts of data or performing complex processing.

Characteristics of computers

The same basic structure as in smartphones and tablet devices

There is no big difference between the contents of a PC and those of a smartphone or tablet device. In many parts, items with the same functions are used with the same roles, including the electronic components used and the basic structures. The major difference is the expandability. Peripheral devices can be connected and used and in some models it may even be possible for the users themselves to replace components.

Furthermore, on most models, there are input devices such as a keyboard and mouse and a power supply is built into the main body. In other words, there are many possibilities for plating to play a role.

Here I will focus on the parts that are standard on computers but also specific to computers. I will talk about some plating that is used in different situations to those I explained for smartphones and tablet devices in the last episode.

What is the difference between computers and smartphones / tablets?

Difference in expandability

When we compare computers with smartphones and tablets, one major difference we can give is their expandability.

With PCs, it is possible to connect peripheral devices (such as a keyboard, mouse, display and external hard drive) to various types of connector for use. As I said in Episode 5, plating (generally nickel plating) is used on the parts of connectors that require durability and electrical conductivity. There is also a lot of plating used on the peripheral devices themselves.

Large sets of data can be stored

In recent years, there has been a spread in the use of cloud storage (in which data is stored on an external storage device such as a server via the Internet). There are now even some computers emerging that do not have hard disks. It may be tempting to think that the era of the hard disk has ended, but the storage devices used in the cloud are themselves made with hard disks. A hard disk is essential for the handling of large volumes of data. They are also used in car navigation systems and in the recording devices on televisions. There are still many areas where hard disks are playing a role. Today, hard disks with TB (terabyte*1) class capacity are sold at easily purchased prices. The level of storage capacity that was previously server class can now be used easily in the home.

*1 TB (Terabyte): 1 TB = Approx. 1,000 GB (gigabytes) = Approx. 1,000,000 MB (megabytes) = Approx. 1,000,000,000 KB (kilobytes) = Approx. 1,000,000,000,000 B (bytes)

What is a hard disk?

Why are hard disks used?

The main reasons for the use of hard disks in PCs and servers are that they have remarkably increased storage capacity, they have become easier to use and they are low cost. As written above, TB class hard disks are now included in standard PCs. Individual hard disk drives (HDD) for use as external memory devices can also be purchased at electrical stores at a reasonable price.

The ultraprecise structure of hard disks

As shown in the video, hard disks have a disk-shaped magnetic body (storage medium) that is rotated at high speeds and the head is moved to read and write the data. In order to make this reading and writing of data possible, it is necessary to bring the head close to the disk (magnetic body). In other words, the head must be brought close to the disk as it is rotating at high speed. It is easy to imagine how any irregularity on the disk surface would result in contact with the head and cause failure. On the other hand, if the head is not brought close to the disk, then there may be problems in the reading of the data.

The accuracy of the gap between the rapidly rotating disk and the head can be likened to the accuracy required to fly a jet airplane at several tenths of a millimeter above the runway. This is how flat the surface of the disk must be and it is plating technology that is used to achieve it.

The storage capacity as a hard disk drive (HDD) is determined by the amount of storage per single disk (platter) multiplied by the number of disks included. As the accuracy of the plating improves, the amount of storage per disk (platter) increases and so the total storage capacity of the drive increases.

Nickel plating and hard disks

We cannot talk about hard disks without talking about nickel plating!

Hard disk drives (HDD) are made from a large number of components and nickel plating is used on many of them. However, the same nickel plating is used for various different purposes.

As shown below, the various functions of nickel plating are put to use in the construction of a hard disk drive.

  • Aluminum disk (surface preparation) [Non-magnetism, smoothness, strength]
  • Swing arm/Magnetic head [Non-magnetism, strength]
  • Spindle motor [Non-magnetism, lubricity]
  • Actuator [Non-magnetism, strength]
  • Frame (main body case) [Magnetic shielding, strength, dust-proofing]

Plating model introduction (Hard disks)

Let me introduce a model of the surface processing up to the magnetic film formation, with a focus on the plating performed on the hard disk substrate.

Pre-treatment process (Zincate treatment)

(1) Remove the oxide film
The first step in the plating is to perform degreasing and etching to remove the oxide film on the aluminum.

(2) Form a zinc substitution layer
The second zinc substitution treatment adds a zinc film to create a situation where plating will more easily attach.

Surface preparation (Electroless nickel plating)

(3) Produce the first plating
Use a type with a high phosphorus (P) content and produce a non-magnetic and smooth film.

Produce a magnetic film (Sputtering)

(4) Produce a magnetic film
Form a magnetic film on the surface using sputtering, which is a type of dry plating.

The technology of plating has advanced together with computers

Computers have continued to advance dramatically ever since their arrival. Functions and performance equivalent to the level of the supercomputers of the past can now be used in the home. Plating has played a role in making this possible.

In 1997, IBM announced that they had made the manufacturing of higher performance components possible through wet plating technology. Ever since then, plating has played a role as a key technology in high-tech devices such as computers.

Furthermore, the importance of plating will no doubt continue unchanged as the technologies advance.