Can colleagues be considered friends in the workplace?

sure.
But even if they are friends, they may be close or distant.
With some friends, you can treat each other sincerely; with some friends, you need to keep in touch; with some friends, you should maintain regular contact and treat colleagues as friends. In fact, the same principle applies.
Of course, when you ask this question, you probably want to say that there are to some extent relationships of interest among colleagues in the workplace.
After all, the company department only has so many resources, and the pie is so big. For example, if you get more, he will get less; for example, if you get the upper hand, he will not get Y.
Is it human nature to "see profit and forget one's righteousness"? I don't know
But when the benefits are great enough, it is possible to betray your friends.
After all, there is an old saying that goes well: Everything has a price, and if you can't buy it, it's probably just because the price isn't quite there yet.
Therefore, when making friends among colleagues in the workplace, you have to judge your interests and exercise discretion.
For some colleagues who have conflicts of interest with you, such as your competitors, you need to keep an appropriate distance. Everyone can work together on official business and cooperate with each other. It is better to meet in private and become acquaintances;

Some colleagues have a community of interests with you, such as your close subordinates, so you should care more and love them more. You can also talk about your inner feelings and treat each other sincerely. When there are difficulties, you can work together;
Some colleagues are distant allies with you, such as cross-department colleagues. You can maintain regular contact, occasionally communicate with each other, exchange professional experiences, and be careful not to gossip. After all, you don’t know that they are competing with you. What's the relationship?
The above three examples can actually be regarded as friends, but there is a difference in closeness and appropriateness.
Of course, I must also remind you that the judgment of interests here is a dynamic thinking.
Churchill said: There are no permanent friends, no permanent enemies, only permanent interests. The identities of friends and enemies may change with time and circumstances, but the nature of interests is eternal. Therefore, your competitors , your conflict of interest may one day have the opportunity to become your ally or even confidant. Therefore, you must view it dynamically and handle it flexibly in order to move forward better and more smoothly in the workplace.